Thursday, December 31, 2009
We can assume most or all of the migrants would have continued eastward along the coast of what are now Pakistan, India and Bangla Desh. Sri Lanka would, at that time, have been part of the mainland, so they would have passed through that region as well. The question is whether or not they left colonies in place as they traveled, or simply bypassed South Asia altogether, gradually progressing eastward as a mobile unit. Everything depends on how we interpret the genetic, archaeological and ethnographic evidence.
One possibility is a so-called wave of advance, with each generation taking root in a particular spot and subsequent generations moving on only when feeling increased pressure as the region becomes saturated. This would produce not so much isolated colonies as an ever growing society continually expanding in all possible directions. If this had been the case, then we would expect to find evidence that the Out of Africa migrants expanded upward into all inhabitable regions of South Asia before continuing east along the coast -- the migration would not in fact have been a coastal migration at all, but a progressive saturation of much or most of the South Asiatic peninsula.
There is in fact some evidence consistent with such a wave of advance, particularly since so many tribal groups can be found well to the north of the coastal region. On the other hand, if the migrants moved on simply due to population pressure, there would have been no coastal migration at all, there would have been an advance in all directions, leaving numerous archaeological sites, and the alleles found throughout central and northern Asia today would be far older than any found further along the coast -- which is decidedly not the case. In fact some of the oldest evidence of the migration, both archaeological and genetic, can be found in Southeast Asia and the Sahul.
Which tells us that the migrants must have had a coastal culture, constraining them to the ocean front as they progressed, another example of the power of tradition over the sort of Darwinian adaptation favored by functionalism (since hugging the coast meant always having an uncertain and unreliable water supply). So if there was a "wave of advance" it would have been confined to the coast. Another possibility is that they could have traveled largely in boats, leaving an occasional colony behind from time to time. Or, possibly, they could have bypassed South Asia altogether, progressing very rapidly along the coast by boat. (While this seems unlikely it's one of the possibilities proposed in Soares et al.: "an origin of haplogroup M in East Asia and a later migration back into South Asia.")
What I presently think most likely was a gradual migration, with the migrants moving largely along the seacoast by boat, leaving various colonies behind as they went, eventually progressing beyond South Asia to Southeast Asia, and what is now Indonesia, which would have been a large body of land at that time when the ocean level was much lower than it now is, as well as many other places in that same general area, including the Sahul (New Guinea and Australia linked at that time by a substantial land bridge).
Something must then have happened, however, centered in South Asia, some sort of major event, a disaster . . .
(to be continued . . . )
Wednesday, December 30, 2009
Although there is evidence of Neolithic and more recent expansions in the Arabian Peninsula, mainly detected by (preHV)I and JIb lineages, the lack of primitive autochthonous M and N sequences, suggests that this area has been more a receptor of human migrations, including historic ones, from Africa, India,It is difficult to assess what this absence of evidence might mean. It's possible the migrants bypassed this region, possibly by boat, or that there was simply never any expansion northward from the coast, into what would have been hostile desert country, or that the descendants of any colonies left behind in this area simply died out over time or were possibly wiped out or assimilated by groups that entered the area much later. In any case, we see little or no evidence of their presence until we reach the South Asiatic peninsula (present day Pakistan and India).
Indonesia and even Australia, than a demographic expansion center along the proposed southern coastal route ("Mitochondrial DNA structure in the Arabian Peninsula," Abu-Amero et al., BMC Evolutionary Biology, 2008).
The differences are cultural as well as genetic, but cultural issues, aside from those centered on language, are rarely discussed in the population genetics literature. Musically there is an enormous gap, especially with vocal music, which is almost exclusively monophonic, with great emphasis placed on solo singing, often of a highly embellished and even virtuosic nature. In strong contrast to the typical voices of Subsaharan Africa, relaxed and open-throated, the Arabic and Persian peoples of this region tend to sing with very tense, narrowly constricted voices.
Whereas most Subsaharan music emphasizes relatively short, simple and unembellished motives, often tossed back and forth among individual singers or in call and response fashion, the music of the Middle East (and North Africa) favors long, elaborately woven melodic lines, often of great intricacy and subtlety, accompanied by instruments playing variations of the same line in a style usually referred to as "heterophony." The contrast with Sub-Saharan Africa isn't universal, and there are in fact certain types of singing based on short phrases tossed back and forth in call and response style -- but almost always with tense voices and in unison, as polyphonic singing is extremely rare if not entirely absent from the entire region. This type of vocalizing is quite different from the open-throated, highly group-oriented, often elaborately interwoven part singing that would probaby have been characteristic of HMC, and seems likely to have developed during a much later period.
Moving on to the next stage of our hypothetical GM journey, and acknowledging that the point I'm about to make will be hotly contested by some, the genetic evidence for HMP and its descendants throughout the entirety of South Asia appears problematic. And the same is true for the cultural evidence. I've already displayed one phylogenetic map for mitochondrial DNA (mtDNA), based on a revised molecular clock that places all the M clades for South Asia at later date than those for Southeast Asia, a very surprising result considering that South Asia represents, in purely geographic terms, an earlier stage along the presumed GM path (see the illustration from the article Correcting for Purifying Selection: An Improved Human Mitochondrial Molecular Clock, as reproduced in Post 262). The molecular clock is undergoing many revisions these days, so any one version of it cannot be regarded as definitive.
But there are other results as well, also reported in recent posts, that present what can only be described as an equivocal picture for this entire region. For example, as reported in Post 264, Cordaux et al., who could not, in 2003, find "any unquestionable genetic signature of the ~60,000 year old migration from Africa to Sahul following the postulated southern route," suggested that "in India the genetic traces of early migrations along the southern route" might have been "erased by the subsequent migrations which shaped the present-day mtDNA gene pool of India."
On the other hand, a more recent study published in 2009, Updating [the] Phylogeny of [the] Mitochondrial DNA Macrohaplogroup M in India, by Adimoolam Chandrasekar et al., concluded that "the basal diversity (37 nodes) and founder ages (57,000–75,000 years) of macrohaplogroup M in India reveals [an] initial settlement of [the] African exodus in India. . . several Indian mtDNA M lineages are deep rooted and [have an] in situ origin." Since the Chandraseka paper doesn't challenge the findings of the Cordaux group, it's hard to know what to make of the above conclusion, or of any of the genetic findings for this very complex region, which must be regarded as provisional until larger population samplings become available.
As I've already argued on this blog (e.g., Posts 259 et seq.), certain cultural evidence is consistent with the more problematic genetic findings, both pointing to a serious gap, to some extent an extension of the gap we found in the Middle East, continuing throughout the length and breadth of South Asia as well. As far as the musical evidence is concerned, stylistically both the "classical" court and religious-oriented music and the more "folk-oriented" village music of both Pakistan and India, together comprising an extraordinarily homogenous style family, can be seen as an extension of the traditions of Middle Eastern music, as described above. I recall a private conversation years ago with a leading authority on Indian music, Harold Powers, who confided in me his conviction that Indian classical music was heavily influenced by Moslem traditions, a theory he dare not publish, as it would have made it impossible for him to continue his research in India.
The situation with the tribal peoples of India (and also many of the lower caste groups, who probably originated as tribals) is more complex, largely because they have not been subject to anywhere near the degree of anthropological or ethnomusicological attention as tribal groups to the East and Southeast. Many are, nevertheless, represented in the Cantometric database, and the picture presented there is of a fairly uniform mix of relatively simple singing styles, characterized in many cases by call and response patterns, and in a few cases polyphonic, but completely lacking any sign of what I've called the "African signature," i.e., hocket and/or interlock, yodel, counterpoint, etc., and no sign of the sort of hocketing instrumental ensembles so commonly found in both Africa and greater Southeast Asia.
There is also some very interesting, though inconclusive, linguistic evidence consistent with the same gap, which might or might not be significant, as well as a possible series of major population bottlenecks produced by the eruption (ca 74,000 ya) of Mount Toba, which could have produced such a gap in both the genetic and cultural picture. I won't go into these questions any further here, since I've already discussed them at length in various earlier posts. We should nevertheless keep all of the above in mind as we attempt to follow the peregrinations of our pioneering Out of Africa migrants along the southern route.
(to be continued . . . )
Tuesday, December 29, 2009
The next question that comes to mind is: how did they obtain water? A migration along a river coast almost guarantees a plentiful supply of fresh water, but traveling along an ocean coast is a completely different matter. The mystery is compounded by the especially difficult conditions afforded by the Indian Ocean coast, where precipitation is controlled by the monsoon cycle: very little rain most of the year; much too much during the summer monsoon season.
If proceeding on land by foot, they would have been completely at the mercy of the law of large numbers, i.e., their slow progress would have meant submission to the overall statistical trend, which would have left them completely without water for months on end during at least some parts of their journey. If proceeding by sea, they would have been moving more quickly and could have gotten lucky, i.e., they could have taken advantage of an anomalous period during which rainfall might have been more plentiful than usual during months when rainfall would ordinarily have been extremely sparse or nonexistent.
The means of transportation is related to other issues as well. If, for example, it took a thousand years to get from the Bab El Mendab to the Indus Delta, where would the tremendous population generated in all that time have expanded to? According to Stephen Oppenheimer, the land mass to their north would have been uninhabitable "until after 50,000 years ago, when a moist, warm phase greened the Arabian Desert sufficiently to open the Fertile Crescent" (The Real Eve, pp. 129-30).
All indications, therefore, are that they would have had to move very quickly across the coast, most probably by means of some sort of oceangoing vessels, which could have carried them long distances within
very short periods of time. The entire crossing from the Horn to the Sahul could, conceivably, have taken only a few hundred years and, if conducted at top speed, less than a hundred. Which leaves open the possibility that only a few or possibly no colonies might have been established over long stretches of their passage.
The Indus Delta would certainly have been a major waystation. First, it would have offered a plentiful supply of fresh water, which may well have been badly needed. Second, it would have presented an interesting option: continue along the Indian Ocean coast, or veer north along the coast of the Indus. If this were the voyage of a practical people, the northern route, with its plentiful water supply would have been the only option, especially given the almost inevitabe hardships that would already have been caused by unreliable and irregular precipitation. I have a feeling there must have been a split at that point, with at least some of them following the river northward, most likely along the western coast, and the rest continuing eastward, as before. My reasons will become clear as we proceed.
As I see it, due to the considerable hardships entailed by their decision to forge ahead, those continuing eastward would have been motivated largely by a desire to explore.
(to be continued . . . )
Monday, December 28, 2009
Before considering the GM, let's review what we think we know about its progenitor, HMP (the Hypothetical Migrant Population), based on our earlier discussions of this issue (see Post 252 et seq.).
1. HMP must have been more Pygmy-like than Bushmen-like morphologicaly, but we can't be sure if they also had short stature.
2. They probably had bows and arrows, with poison tips.
3. They probably lived in beehive huts.
4. They were almost certainly hunters and gatherers.
5. They very likely would have vocalized in some form of P/B style, including both interlock and yodel, though possibly not in the more complete and complex form of their ancestors, HBP.
6. They would have had certain instrumental traditions: the musical bow, an inheritance from HBC; hocketing pipe ensembles, possibly inherited from HBC; hocketing trumpet, horn and panpipe ensembles, slit drums, simple leg xylophones, and stamping tubes, all probably representing a somewhat later development. Such instruments are found in abundance both in and out of Africa.
7. They would have had a tradition of accompanying their singing with some form of percussion, either clapping or by the use of simple idiophones, such as beating on sticks. The ancestral percussion tradition would have been extremely sophisticated and complex rhythmically, but since we find little evidence of comparable complexity outside of Africa, it's possible that the rhythmic accompaniments of HMC were less complex.
8. It seems very likely that they would have spoken some type of tonal language, since almost every language now spoken in Subsaharan Africa is tonal, including Khoi-San, often regarded as an archaic survival.
9. HMC would, in all likelihood, have maintained many if not all of the most important core values of HBC: strong emphasis placed on egalitarianism, relative gender-equality, cooperation, conflict avoidance, individualism, and the sharing of vital resources, with strong sanctions against competition and violence. Since all of the above are characteristic of so many other hunting and gathering peoples worldwide, it seems safe to infer that these values would have been inherited from HBC via HMC. We mustn't forget, however, that not all indigenous peoples value non-violence and some strongly value competition, so we will need at some point to account for this very fundamental cultural shift.
10. Since shamanism of some kind, though not always in the strictest sense of the term, is found both in and out of Africa, and is in some sense almost universal, it seems safe to infer that it was, in some form or other, an important part of both the healing practices and religious awareness of HMC.
11. Since intricate wood carving and mask making traditions are found in both Africa and among certain other groups outside of Africa, with striking resemblances in some cases between the two, it seems logical to infer that similar traditions would have been part of HMC. We can also infer, on the basis of very similar practices found both in and out of Africa that scarification, body painting, tatooing, tooth filing, and other forms of "body art," are likely to have been part of the HMC cultural "package" -- though in some cases independent invention can't be ruled out as a possibility.
(to be continued . . . )
Saturday, December 26, 2009
two genes involved in brain growth and development. Deleterious mutations of both ASPM and Microcephalin are involved in recessive primary microcephaly, together with at least four other loci identified to date (p. 10945).As the authors explain, both genes exist in two forms, original and "derived," with estimates for the origin of the derived states, designated with the suffix "-D," as 5.8 thousand years ago for ASPM-D and 37 thousand years ago for Microcephalin-D.
According to the theory presented in this paper, there is a relationship between
the distribution of tone languages and the geographical structure of ASPM-D and MCPH-D. Those areas of the world where the new alleles are relatively rare also tend to be the areas where tone languages are common. As previously discussed, the effects of ASPM-D and MCPH-D on brain structure and functioning remain largely hypothetical, but it is entirely plausible that they influence the cognitive capacities involved in processing phonological structures and thereby lead to linguistic biases of the type suggested above (ibid. -- my emphasis).The distributions in question are presented in the following maps:
Theoretically, the Old World regions with the fewest instances of both genes are where the greatest number of tone languages are to be found. Or, to put it another way, there would appear to be a correlation between the frequency of the original forms of both genes and the frequency of tone language. And what Dediu and Ladd are claiming is a cause and effect relationship:
The relationship between genetic and linguistic diversity in this case may be causal: certain alleles can bias language acquisition or processing and thereby influence the trajectory of language change through iterated cultural transmission.
What is being claimed, in other words, is that the presence of the newer, derived forms of the genes, will tend, over time, to influence the evolution of language such that tone languages will eventually become non-tonal.
On its face, these results would look to me like a perfect example of the logical fallacy called "cum hoc ergo propter hoc" (Latin for "with this, therefore because of this"). In other words, correlation does not imply causation. It would seem more likely that both the genetic distributions and the linguistic distribution are due to underlying historical factors, possibly the same historical factors we've already been considering in the last few posts.
The authors are aware of the problem, however, and claim to have controlled for both geographical and historical factors:
To control for the effects of geography and shared linguistic history on our results, we compared geographic, genetic, typological linguistic, and historical linguistic distances between all pairs of populations in the sample (p. 10946).
Their conclusions are based on mathematical models that seem rather abstruse, to say the least. For example:
Individually, the Mantel correlation with geography for tone is
r = 0.169, P = 0.015; for ASPM-D, r = 0.074, P = 1.000 (because of Holm’s multiple comparisons correction; ref. 56); and for MCPH-D, r = 0.543, P less than 0.001. Each of tone [sic], ASPM-D, and MCPH-D have low but significant spatial autocorrelations (62): Moran’s I (63) is 0.178, 0.164, and 0.121, and Geary’s c (64) is 0.634, 0.438 and 0.718, respectively, P less than 0.001 for all, suggesting that, potentially, geographical factors might explain the observed relationship. However, the (partial) Mantel correlation between tone and the pair ASPM-D/MCPH-D is r =0.333, P less than 0.001, and, when controlling for geography, it decreases only slightly and still remains highly significant, r = 0.291, P =0.003, showing that geography is not a good explanation for our empirical findings (ibid.).
While the above goes well beyond my present math skills (as a high school student I was a math whiz, but most of what I learned then has been long forgotten, sad to say), it seems clear that any attempt to assess the distribution of tone languages in either geographical or historical terms is going to be seriously affected by the very same gap that I've been pointing to over and over -- and trying to understand.
It might seem reasonable, in view of the author's analysis, and especially in view of their very impressive mathematics, to forget about this gap and simply accept that the distribution of tone languages must be due to the influence of genetic factors having nothing to do with either geography or history. But there is a serious problem with their reasoning, a problem which should serve as a warning to anyone relying too heavily on mathematical models and too little on common sense:
While it might be possible to attribute the distribution of tone languages to an evolutionary process determined by certain genes, what is it that has determined the distribution of the genes? On this question, as far as I can tell, they have nothing whatsoever to say. If the dates for the origin of each genetic marker have been determined, as they claim has been done, then clearly each must also have had a very specific place of origin as well. And must therefore have migrated since then along a very specific path or paths from that point. Which tells us that when considering the distribution of both the genes and any effects those genes may have had, on language or anything else, neither geography nor history can be ignored.
Much as we might want to explain it away with fancy schmancy genetic and mathematical models, the gap remains.
[Added at 10PM: I've been thinking a lot about this article and the questionable reasoning behind it, and wondering more and more why it was even accepted for publication and why the results have been so widely and uncritically reported. Meanwhile Dediu and Ladd are taking these results and running with them, writing followups that have also been published in respectable academic venues. Their work is now being cited in the work of other cognitive scientists as a beautiful example of how cultural evolution is determined by brain biology, and, unless someone with some influence (I have zilch) rings a bell, will soon take its place as part of the accepted wisdom of the day, among cognitive scientists, linguists and, no doubt, anthropologists.
For this reason, it is all the more important that I make myself as clear as possible regarding the thinking behind this paper. It's not only that they are clearly wrong in claiming that the gapped distribution of tone languages in two very different regions of the Old World is due to the effects of ASPM and Microcephalin, but there is also no reason to assume any sort of cause and effect relationship between the presence or absence of these genes and the existence of tone language, even within either of these two regions. The genes and the tone languages are, in all likelihood, totally unrelated. Even if there were a perfect one to one correspondence between the three distributions (and there is not), this would most likely be due to the influence of more fundamental evolutionary factors underlying the history of all three, factors totally independent of any possible relation between genes and language other than the simple fact that both the genes and the languages were carried from their points of origin to their present locations by the same migrating populations.
While I'm reluctant to attach too much importance to the genetic distributions reported in this particular paper, since the authors were working with seriously incomplete evidence (Australia and New Guinea were deliberately omitted from consideration due to lack of reliable genetic data), it's worth mentioning that the distribution they appear to have found for the original (non-derived) form of ASPM might provide additional genetic support for the gap I've been making so much of. I'm wondering whether other, completelly unrelated, genetic markers might eventually be found with more or less the same geographical distribution, due to essentially the same population history, marked by the very same gap.]
Wednesday, December 23, 2009
Here, for example, is what Richard Cordaux et al. have to say, in their paper, Mitochondrial DNA analysis reveals diverse histories of tribal populations from India, 2003. And by the way, Mark Stoneking, one of the leading figures of population genetics, is one of the co-authors:
In summary, although the data support a recent India– Australia connection, we could not find in Indian tribals any unquestionable genetic signature of the ~60,000 year old migration from Africa to Sahul following the postulated southern route. A possible explanation would be that such migration never occurred along that route. Alternatively, the early migrants from Africa may have made their way to Sahul following the southern route without settling in India. Another possibility, which is probably the most reasonable one, is that in India the genetic traces of early migrations along the southern route were erased by the subsequent migrations which shaped the present-day mtDNA gene pool of India (p. 262 -- my emphasis).Whether the subsequent migrations came in the direct aftermath of the bottleneck I think I'm seeing, or at a much later time, is not clear. What is clear is that, at least as far as these authors are concerned, there is a genetic gap, at exactly the same place we find all the other gaps.
[Added at 3:52 PM: Here is what Kivisild et al had to say on this matter, in 1999:
Both western and eastern Eurasian-specific mtDNA haplogroups can be found in India together with strictly Indian-specific ones. However, in India the structure of the haplogroups shared either with western or eastern Eurasian populations is profoundly different. This indicates a local independent development over a very long time period ("The Place of the Indian mtDNA Variants in the Global Network of Maternal Lineages and the Peopling of the Old World," p. 14 -- emphasis mine).]
Nevertheless, Maju could still be right in questioning my interpretation of the gap, because it's possible that it's the result of more recent historical developments having little or nothing to do with the original Out of Africa migration. And it may or may not be supported by the genetic evidence, depending on whose research you prefer to follow. I want to consider all possibilities and to make clear that I'm not in love with the interpretation I've been presenting -- for me it seems like the simplest and most reasonable interpretation, but I'll be happy to accept any explanation that makes sense, even if the events producing the gap can be traced to some other event(s), such as, possibly, the LGM (latest glacial maximum), or migrations dating to the Neolithic, or even relatively modern events due to colonialism. If Maju or anyone else would like to put together a coherent alternative explanation for all these gaps, I invite them to do so as a comment, and I'll bring it over here into the posts. What I will not accept is a dismissal or denial that any such gap exists. At the risk of repeating myself: the gap is there -- it is real -- it must be accounted for.
Further confirmation of the "southern route" hypothesis comes from a very recent paper, just published in the December edition of Science, Mapping Human Genetic Diversity in Asia, by "The HUGO Pan-Asian SNP Consortium":
More than 90% of East Asian (EA) haplotypes could be found in either Southeast Asian (SEA) or Central-South Asian (CSA) populations and show clinal structure with haplotype diversity decreasing from south to north. Furthermore, 50% of EA haplotypes were found in SEA only and 5% were found in CSA only, indicating that SEA was a major geographic source of EA populations (from the Abstract -- my emphasis).Evidence for important founder effects in South Asia, as suggested by both Oppenheimer and Soares et al., comes from another recent paper, published in Nature last September, Reconstructing Indian population history, by David Reich et al: "Allele frequency differences between groups in India . . . [reflect] strong founder effects whose signatures have been maintained for thousands of years owing to endogamy" [my emphasis]. So strong are these effects that they are believed to have an important influence on the health of the population generally:
The large number of Indian lineages with a history of founder effects is consistent with the notion that South Asia could have been subject to a major population bottleneck during the Out of Africa migration, possibly due to a catastrophic event such as the Toba explosion, a Tsunami, major flooding, or a widespread, long-lasting drought. As I suggested in my "Echoes" paper, an event such as this could have had a major impact on the culture of the surviving groups, which could explain both the absence of much trace of P/B musical style, and the absence of tone language in this region. In other words, the "strong founder events" reported in this paper may have been a major factor in human evolution, genetic, morphological and cultural, at a crucial moment in history.
The widespread history of founder events in India is also medically significant because it predicts a high rate of recessive disease. In Finland, there is a high rate of recessive diseases that has been shown to be due to a founder event, and that has resulted in a minimum FST of 0.005 with other European groups. Our data show that many Indian groups have a minimum FST with all other groups that is at least as large. . .By showing that a large proportion of Indian groups descend from strong founder events, these results highlight the importance of identifying recessive diseases in these groups and mapping causal genes [my emphasis].
As is well known, certain tribal groups in South Asia have been described as "Australoids," due to their striking resemblance to Australian aboriginal peoples, which has suggested to many an archaic connection between the two regions. As I wrote in "Echoes of our Forgotten Ancestors,"
Is it possible that Australia, populated, at least 10,000 years after the Toba blast, could have been occupied by one of the altered survivor lines out of South Asia? Could that also explain the musical discrepancies between Australia and the rest of the out-of-Africa P/B style singer-players? Could that population have simply lost its polyphony, its hocketing, its panpipes, etc. asWhile a genetic connection between south Asiatic tribal peoples and Australian aborigines has been debated for years, a recent paper on that topic, Reconstructing Indian-Australian phylogenetic link, by Satich Kumar et al., though modest, does support such a possibility:
a result of an ages-old natural catastrophe, and been forced to invent itself anew?
Our complete mtDNA sequencing of 966 individuals from 26 relic populations of India identified seven individuals from central Dravidian and Austro-Asiatic tribes who share two basal synonymous mtDNA polymorphisms G8251A and A9156T with
the M42 haplogroup, which is specific to Australian Aborigines. . .
Our results showing a shared mtDNA lineage between Indians and Australian Aborigines provides direct genetic evidence that Australia was populated by modern humans through south Asia following the "Southern Route" (pp. 1-2 -- my emphasis).
The cultural connection would be more convincing if the music of Tribal India were stylistically close to that of native Australia, but it is not. Nevertheless, the absence of both the African musical "signature" and tonal languages in both Tribal India and Australia, whereas both of these important cultural indicators can be found in abundance everywhere else along the Out of Africa path, does seem consistent with genetic evidence pointing to an archaic connection between the two regions. The unusual features attributed to "Australoid" peoples are also consistent with a genetic bottleneck and subsequent founder effect centered in South Asia during the great migration eastward. If the first wave of migrants had already arrived in Southeast Asia by this time, they would have been upwind from the Toba blast and, assuming this as the cause of the bottleneck, relatively unaffected.
Tuesday, December 22, 2009
As I've already mentioned, genetic anthropologist Stephen Oppenheimer has pointed to a very similar gap in the genetic evidence, which led him to propose a major bottleneck event stemming from the eruption of Mount Toba. While the timing of the Toba eruption makes Oppenheimer's interpretation problematic, the genetic evidence he cites does indeed suggest that something very unusual must have happened in South Asia very early on, at what might well have been a critical turning point in human history.
With all this in mind, let's return to the genetic map I presented two posts ago:
(Click on the above to enlarge the image.) The map, representing a phylogenetic tree based on mtDNA (mitochondrial DNA, representing female lineages only) is from a recently published article, Correcting for Purifying Selection: An Improved Human Mitochondrial Molecular Clock, by Pedro Soares et al., June 2009. (Among the co-authors, by the way, is Stephen Oppenheimer.) What makes this tree especially interesting is, first of all, the effort by the authors to correct for the effects of natural selection, and secondly, the introduction of timing estimates based on what the authors claim to be a new and improved molecular "clock." The number displayed next to each node represents their estimate for the origin of that node, in thousands of years. Thus, for example, the origin of M is given as 60.6, i.e., 60.6 thousand years ago.
Each node is color coded according to its most common geographical occurrence, as indicated in the key at the upper right. What's unusual here is the fact that the M haplogroups for South Asia (in violet) are presented farther to the right, and slightly lower, than the M haplogroups for East Asia (in blue), implying that the South Asian haplogroups appeared at a later date than those for East Asia. And sure enough, the date for South Asian M is 49.4, while that for East Asian M is 60.6. If the Out of Africa migration proceeded in an orderly, predictable fashion, from west to east, we would expect to find the oldest haplogroups in South, not East, Asia.
So once again we must ask: what gives?
The first point to be made regarding the new research is the fact that the dates they've come up with "render an out of-Africa dispersal prior to the Toba eruption in Sumatra at ~74 kya less likely." Given that Oppenheimer is one of the co-authors, this is a particularly significant conclusion. Nevertheless, the inconsistency between South and East Asia must be accounted for:
In the context of the southern-coastal-route model, it should be noted that although the distribution of haplogroup M has also been used to support the southern route model, the age of haplogroup M in India, at 49.4 (39.0; 60.2) kya, is significantly lower than in East Asia, at 60.6 (47.3; 74.3) kya . . . At face value, this could suggest an origin of haplogroup M in East Asia and a later migration back into South Asia, suggesting that it may have been a ‘‘pre-M’’ lineage that initially crossed South Asia. . . Southeast Asia may [therefore] be the point of origin of haplogroup M . . . Alternatively, if M dispersed with N and R through South Asia, M may have been caught up in a subsequent bottleneck and founder effect so that its age signals the time of re-expansion rather than first arrival (p. 752 -- my emphasis).
There will, of course, be a great many refinements and no doubt revisions of all the many phylogenetic trees that are now being published. Nevertheless it seems clear, not only from these results, but others already published, that the gap I've noted, based largely on cultural evidence, is reflected in the genetic evidence as well. While such a gap might at first seem to be a stumbling block in our understanding of the earliest migrations of modern humans out of Africa, it is also, as I see it, a tremendously important clue, which could explain a great many other mysteries, some of which are so obvious as to have been taken for granted by the great majority of investigators.
(to be continued . . . )
Monday, December 21, 2009
This is thanks to Maju, who in a comment to the previous post, questioned an aspect of the above display that puzzled him: the presence of A3 and A4 in northern South Asia, in the first, second and fourth minimaps. Now A3 and A4 stand for two variants of P/B style, contrapuntal interlock and canonic interlock, found in the Caucasus and Europe, usually in refuge areas associated with mountainous terrain. And the reason I initially placed them in South Asia was because there was genetic evidence linking mtDNA haplogroups U5 and HV (see Oppenheimer, The Real Eve, p. 145) with the origins of early Europeans in what is now Pakistan and western India.
In order to account for the population of Europe by descendants of HMP, we need to find a pathway via which some subgroup would have branched off from the main body moving steadily eastward along the southern route. And it occurred to me that the most natural northward path after the Arabian coast would have been along the Indus River. Lo and behold, if our proto-Europeans had made their way far enough along the Indus valley, they might well have been sufficiently far from the effects of either Toba or the Tsunami I've depicted to have survived with their HMC traditions (including A3 and A4) intact. And that would explain why we find P/B variants A3 and A4 so abundantly in Europe as well as Southeast Asia, Melanesia, etc. Which is why I placed A3 and A4 where I did.
Now the reason I'm bringing this up again is because I just discovered that there is in fact an important pocket of tone language in exactly the same region where I placed A3 and A4, the upper reaches of the Indus, which, according to my hypothesis, could have been an important starting point for a migration of U5 and/or HV into the Caucasus and from there to Europe. And if this group had been insulated from whatever disaster befell it's cousins in Southern Asia, that could explain the survival of tone languages in this region. In fact, tone languages seem to have survived, like P/B, only in regions that would not have been affected by either the Toba explosion or a Tsunami centered south of India.
The linguistic map of tone languages shows only one in this general area, Kalami. In fact the entire region, unlike any other in either Pakistan or India, is rich in tone languages:
It appears to be the case that a majority of the languages of northern Pakistan (Punjab, NWFP, Northern Areas, and Azad Jammu and Kashmir) are tone languages. If we look at the numbers of speakers of these languages, it appears to be the case that a majority of the people of northern Pakistan are speakers of tone languages (Tonal features in languages of northern Pakistan, Joan L.G. Baart, p. 2).Putting all the pieces together, we see a striking correlation between the survival of the musical style I've been calling "P/B," according to the hypothesis illustrated on these maps, and the distribution of tone languages in the Old World -- specifically, in SubSaharan Africa, Southeast Asia, Melanesia -- and the northern reaches of the Indus valley. The distribution is seen most clearly in the second map, labeled "Bottleneck Event," where only the surviving versions of my musical "super-haplogroup," A -- including A3 and A4 in the upper Indus valley -- are shown.
Sunday, December 20, 2009
The first thing I'd like to call your attention to is the saturation of tone languages in Africa. This map is taken from a remarkable website, The World Atlas of Language Structures Online (WALS), consisting of 141 maps of distinctive linguistic features, and as far as I've been able to determine, it's very unusual for any one region to be dominated by a single trait. The chances of this being a coincidence have to be pretty close to nil. If modern humans originated in Africa, then the earliest languages, including the language spoken by the Out of Africa migrants (HMP), were almost certainly tonal.
The next thing I'd like to call your attention to is the comparable saturation of tone languages in Southeast Asia and also Melanesia -- here too coincidence seems highly unlikely. Since these are areas populated by many indigenous groups, hunter-gatherers or horticulturalists, the saturation of tonal languages is most likely part of a broader pattern of cultural inheritance from HMC, as evidenced by other important features I'll be discussing presently.
If this is the case, then what are we to make of the areas along the same pathway where tone is almost completely absent? The dearth of tone languages in Indonesia, Taiwan, the Philippines, Micronesia, coastal New Guinea and much of Island Melanesia can easily be explained by the relatively recent expansion of Austronesian speaking agriculturalists throughout this region beginning around 8,000 years ago. But India, Pakistan and Australia are not part of this development, and their non-tonal languages are much, much older. Since the very long South Asian coastline represents an important segment of the Out of Africa path, one would expect to find tonal languages here as well. And since both the archaeological and genetic evidence indicates that Australia was a very early, if remote, offshoot from the Out of Africa migration, the total absence of tonal languages on that continent is also extremely puzzling.
A pattern begins to emerge, however, as we realize that essentially the same odd distribution applies to certain other important characteristics, morphological, genetic and cultural, that, taken alone, are equally puzzling. For example, as I've already noted, those peoples in Asia and Oceania closest morphologically to African pygmies (thus likely to resemble HMP -- see Post 254), usually referred to as negritos, are not found at all in South Asia (aside from the Andaman Islands, well to the south and east), but are relatively common in Southeast Asia, the Philippines and Melanesia.
While Africa is famous for its remarkably rich traditions of wood carving and mask design, comparably elaborate artistic traditions are not found until we go beyond South Asia to indigenous peoples in parts of Malaysia, Indonesia and Melanesia, where some of the resemblances to African carvings, both artistic and contextual, are truly striking. If these were were traditions maintained by HMC, as seems very likely, why aren't they found in equal abundance everywhere along the Out of Africa trail?
The same question could be applied to the musical traditions of HMC, dominated as they must have been by P/B style. The "African signature" I've written so much about is essentially absent from the musical practices of both South Asia and Australia. This mystery is discussed at some length in my essay, Echoes of Our Forgotten Ancestors and also on this blog, beginning with Post 12. As I wrote in "Echoes,"
If the original Out-of-Africa group moved uniformly all the way from Africa down the coast of south Asia to the Malay Peninsula and from there down through Indonesia to New Guinea and Australia, as is sometimes claimed, then we musicologists have a problem. While many indigenous groups along the “beachcomber” route sing and play in a manner strongly reminiscent of P/B style, there has to my knowledge never been any instance of such a style found anywhere in Australia (p. 30).
Essentially the same absence applies to the entirety of the Near East and South Asia. In none of these regions have I as yet found more than the faintest traces of P/B, either vocal or instrumental -- no hocket, no interlock, no hocketing pipe, flute, trumpet or panpipe ensembles, no stamping tubes, no hocketing gong or percussion ensembles, maybe the occasional slit drum. Yet once we move into the same region where tone languages, negrito hunter-gatherers, and African-style carvings and masks are found, all the above musical practices, and the instruments associated with them, are also found -- in abundance. So what gives?
The same gap appears in the genetic evidence, interestingly enough. Stephen Oppenheimer has written as follows, regarding
the paradox of the Indian genetic picture, in which the genetic trail of the beachcombers can be detected, but the bulk of Indian subgroups...are unique to the subcontinent, especially among the tribes of the south-east. This is what we would expect for a recovery from a great disaster (The Real Eve, p. 193).Oppenheimer had a very specific disaster in mind, by the way,
“the greatest natural calamity to befall any humans, ever,” the eruption, c. 70,000-74,000 years ago, of Mount Toba, in Sumatra. The explosion was so vast it left a plume of ash over the entirety of India for approximately five years, what Oppenheimer has called a “nuclear winter,” in which almost every living thing in that area would have been wiped out (The Real Eve, p. 82). This is one of the very few events in prehistory that can be precisely dated and measured, since “a metres-thick ash layer is found throughout the region.” ("Echoes," p. 31).
Though the evidence that modern humans were in Asia at the time Toba erupted is both slim and controversial, there is in fact very good reason to believe that some sort of calamity befel HMP's descendants during their great migration eastward. I discussed this possibility at some length in Post 12, where I presented the following map, illustrating how the early history of the Out of Africa migrants, and their music, could have been affected by a disaster of this sort -- in this case, a Tsunami.
In the first little map, titled "Out of Africa," all the arrows are red, representing the five variants of the original "Pygmy/Bushmen" style (A1 - 5 on the Phylogenetic Tree) that, as I see it, must have spread along with the original "out of Africa" migrants, following Oppenheimer's coastal route, all the way to Sundaland and beyond, turning the corner around the Moluccas, I guess and then continuing north along the SE Asiatic coast.
Mini-map 2, "Bottleneck Event," is an attempt to picture a catastrophic event that could account for the musical gap we find between Yemen and Myanmar, where little or no evidence of Pygmy/Bushmen style can be found today. According to Oppenheimer, there is a very similar gap in the genetic evidence, though, as I understand, not everyone agrees about this. As I see it, only some sort of catastrophe at some point from, say, 75,000 to 50,000 years ago, can explain all the very different musical styles we find in the world today, especially the styles
represented in the phylogenetic tree as B2 and B3 and their derivatives. So this map, unlike any other I've ever seen, is not based solely on continuity, but contains an abrupt break, representing the effects of the bottleneck on the various surviving groups.
I'll include one more map before quitting for the day: It's from a recently published article titled Correcting for Purifying Selection: An Improved Human Mitochondrial Molecular Clock. See what you can make of it.
(to be continued . . . )
Saturday, December 19, 2009
I now realize that another, much more significant, aspect of language was staring me in the face all that time, so obvious I simply overlooked it. Almost every single language in SubSaharan Africa is a tonal language, i.e., a language in which differences of meaning are determined by differences in pitch. Thus, if homo sapiens originated in Africa, as is now generally believed, the first language is very likely to have been tonal -- which tells us that, if HBP had any language at all, it too would have been tonal -- and even if they didn't have a fully formed, fully syntactic language (as I suspect they may not have), then whatever vocabulary they had would most likely have contained tonally differentiated phonemes. This observation ties in rather nicely, I must say, with earlier speculations of mine that the development of music may well have preceded, and influenced, the development of speech, because musical notes in and of themselves operate like tonal phonemes (see "Echoes of Our Forgotten Ancestors").
Regardless of whether a fully formed tonal language was part of HBC, such a language was almost certainly employed by HMP -- first, because they were in all likelihood SubSaharan Africans, but also because, unlike clicks, tonal languages are in fact widely found among their descendants. If we expect to conclude, however, that tonal languages were spread via the migration initiated by HMP, along the southern route, we have a problem. A very puzzling gap can be seen in the distribution of tonal languages along this route:
Friday, December 18, 2009
For one thing, the style tends to be watered down, lacking the complexity, subtlety, spontaneity and creative freedom so characteristic of almost all Pygmy and Bushmen music. The counterpoint is often more limited in scope, the degree of improvisation restricted, or in many cases non-existent. Performances tend to be planned in advance and often rehearsed, with a fixed rather than open-ended number of parts.
The social context in which this particular type of music is performed also tends to be far more restricted. In a great many cases, the style is reserved for special occasions, often associated with some of the most important rituals, as though this music were consciously associated with the oldest and most powerful ancestral traditions. In other cases, we find it, as in the "throat singing" of certain Paleosiberian and Inuit groups, characterized as a game (though as Nattiez has demonstrated, this "game" has decidedly shamanistic roots).
It's important to understand that such limitations do not apply among African Pygmies and Bushmen. While certain repertoires are reserved for special ceremonies, such as the girl's elima or the molimo ceremony among the Mbuti, or the Eland or Xhoma rituals among the Ju/'hoansi Bushmen, the style as a whole is a characteristic, spontaneously expressed, aspect of everyday life, as it very likely was for HBC. Whether the same applies to P/B as practiced by HMC is not completely clear, especially since we find "watered down" and contextually restricted forms of P/B among many African groups as well.
Only a very few, rather simple, musical instruments are native to either Pygmies or Bushmen. Most instruments now in use among these groups, such as the drum, the mbira and various string instruments are known to be borrowed from neighboring farming or herding peoples. In fact the only musical instrument commonly found among all three of our "feeder" groups, EP, WP and Bu, is the musical bow, an extremely important instrument that was undoubtedly a part of both HBC and HMC, and is widely found among a great many indigenous groups in many parts of the world.
Of special interest in the present context are the many polyphonic wind ensembles, of pipes, whistles, trumpets, horns or flutes, to be found among certain groups in Africa, organized in a manner very similar to the hocketed interlocking of parts so characeteristic of P/B vocalizing. Typically, each instrument has a single note to play, or in some cases, a repeated phrase, which interweaves with all the other parts to produce a resultant melody, rhythm or polyphonic texture. Since I've already discussed such ensembles at some length on this blog (see Post 38 et seq.), I won't go into detail on their organization here.
The Mbuti perform with hocketed ensembles of single-note pipes called Luma, tuned and kept for them by their Bantu "masters." The BaAka use the mobeke pipe, described as "a small whistle made from the stem of a papaw plant," for the same purpose. Among the Ba'Benzele Pygmies similar pipes are called hindewhu. In all cases, the pipes participate as equal partners with voices in hocketed/interlocked P/B style performances. I would have included pipe ensembles of this kind in HBC, except for the fact that they are not found, apparently, among Bushmen groups, and I've been trying to be as strict as possible with my "triangulation" method.*
Nevertheless, since such ensembles are so common in Africa, with very similar ensembles of pipes, panpipes and trumpets found outside of Africa, in many of the same parts of the world as P/B style vocalizing, it would be very difficult to explain such a link unless the tradition had been disseminated via HMC. Thus, despite the fact that it's not strictly speaking possible to attribute instrumental hocket/interlock to HBC, the worldwide distribution of this tradition can be explained only if it were a part of HMC. The vocal and instrumental forms of P/B are so close stylistically and structurally that the latter most likely developed from the former, possibly only after the proto-Bantu diverged from the ancestral proto-Pygmies and Bushmen.
Hocketed percussion, possibly a development from the very complex polyrhythmic interactions of P/B handclapping, is also an important tradition in many parts of Africa, with important echoes, once again, along the southern "Out of Africa" route. One of the simplest types, stamping tubes, is widely found in Africa, but also along the same southern "Out of Africa" route as so many of the other traditions I've been discussing. In this highly interactive type of music-making, each performer typically has a single tube in each hand, performing only one segment of an intricate melodic-rhythmic resultant pattern, usually repeated over and over.
Though commonly found among many African groups, stamping tubes are not reported among either Pygmies or Bushmen, though similarly interactive rhythmic effects are produced by them using sticks, a practice that could be regarded as prototypical. Since very similar types of stamping tube ensembles are found outside of Africa, and the complexities of the rhythms make independent invention unlikely, despite the simplicity of the instruments themselves, once again we have a musical tradition that could only have been transmitted via HMC.
Much the same could be said of a very simple type of xylophone, made from slabs of wood placed on the lap or legs of the performer, which once again is commonly found both in Africa and along the Out of Africa path, but not reported for Pygmies or Bushmen, thus most likely not directly associable with HBC.
Another instrument of great interest, with a very similar multi-regional distribution, is the slit drum, which is also, like stamping tubes, often played in hocketed/interlocked ensembles. Once again, the distribution of this very important instrument, often elaborately carved and with great ritual significance in certain cultures, can be explained only if it were part of a tradition disseminated via HMC.
*However, hocketed panpipe ensembles were reported among their close relatives, the Khoi-Khoi (Hottentot) cattle herders.
Thursday, December 17, 2009
I've already made what I believe to be strong case for P/B as an equally pervasive and important aspect of the culture of the ancestral group, HBC. What must be considered now is what role, if any, the style played in HMC.
One clue, as far as Africa is concerned, is the very interesting center of P/B style to be found in a region very close to what is widely considered both a possible birthplace of "modern" humans and the staging area for the Out of Africa migration: the Omo River valley in southwest Ethiopia. According to the Cantometric database, the following peoples in this region, all speakers of "Omotic" languages, vocalize at least some of the time using interlocking counterpoint, one of the most distinctive features of P/B: the Ari, Dorze, Gamo, Ghimira and Wolamo. As far as I know, however, the Dorze are the only ones in this region who regularly yodel, another important feature of P/B among Pygmies and Bushmen.
Whether the culture of the Out of Africa migrants was as saturated with this style as the cultures of today's Pygmies and Bushmen are, or whether it might have taken some more or less "watered down" form by that time, is very difficult to say. Judging from the widespread distribution of certain very distinctive features of this very distinctive style, especially in certain key regions along the southern Out of Africa route, it's impossible for me to believe that a very similar musical practice did not play an extremely important role in HMC.
The following are characteristics of P/B widely found among various (though by no means all) indigenous cultures outside of Africa. Assuming a single migration, the culture of the Out of Africa migrants being the only possible link between HBC and the ancestral traditions of all these different peoples, the same characteristics would therefore have played an important role in HMC as well:
1. Simple shouted "hocket," where one voice or one group half sings and half shouts one or two notes, in rapid alternation with other voices or groups;
2. more elaborate forms of hocket, where two or more voices interlock closely together to produce a melodic or contrapuntal resultant;
3. more smoothly integrated interlocking counterpoint, very similar to the above, and also producing resultant effects;
4. imitative or even canonic forms of vocal counterpoint, often resembling simple rounds, but sometimes much more complex;
5. additive structures, where there are as many parts as there are participants, who enter and exit as they please;
6. a continuous flow of sound, with no audible articulation points and alternation of breathing among all participants;
7. wide, disjunct melodic intervals, often producing a "fanfare" type effect;
8. yodel -- many groups in Africa that sing in variant forms of P/B do not also yodel, but judging from the importance of yodel among so many indigenous peoples outside of Africa, HMP almost certainly did;
9. some form of percussion accompaniment, ranging from handclaps to the striking of sticks or simple rattles -- while such rhythms can be extremely intricate and subtle among Pygmies and Bushmen and indeed many other African groups, we don't find comparable rhythmic complexity outside of Africa, at least not among indigenous peoples, which means that HMC may not have had as elaborated a rhythmic sense as their ancestors;
In the next post, I'll discuss instrumental music, which would most likely have played only a minor role in HBC, but must have been far more important and elaborated among the Out of Africa migrants.
Tuesday, December 15, 2009
I'll begin by exploring that first alternative, a single Out of Africa migration. My strategy will be simple. I'll first consider, one by one, the characteristics of HBC that we've already considered, and ask whether it's likely that the same traditions could still have been alive in HMC. I'll then consider possible characteristics of HMC that might differ from HBC.
It's important to remember that our assessement of HBC was based on the examination of three African populations, EP, WP and Bu, whereas our assessment of HMC must be based on non-African traditions as well. Assuming a single Out of Africa event, it should be clear that all non-African cultures everywhere in the world ultimately derive from the culture of the original Out of Africa migrants. I repeat: all non-African traditions, however diverse, can be understood in the most fundamental sense as stemming from HBC as filtered by HMC. While EP, WP and Bu served as "feeders" in the construction of our HBC model, all non-African cultures, especially those of the most traditional indigenous groups, are available as "feeders" in the construction of our model for HMC. While this immeasurably enhances the richness of the possibilities, it also makes the process of hyphothesis construction far more complicated and uncertain.
Let's begin with some relatively straightforward questions. Did the Out of Africa migrants have bows and arrows? And if so, did they use poison arrows? While the use of bows and arrows and arrow poison by HBP remains uncertain (no stone arrow points have been discovered in the tropical forests of Africa -- but most Pygmies and Bushmen traditionally used bone or wood points that would not have been preserved), the widespread presence of bows and arrows both in and out of Africa makes it almost certain that this technology was an important part of the material culture of HMC, from where it would have spread to the rest of the world.*
As for the use of poison tips, on arrows, spears and darts, it seems logical to conclude that this too is very likely to have been an important part of the hunting technology of HMC, especially since such tips can be found among so many hunting and gathering people today.
Did the Out of Africa migrants have beehive huts? HBP almost certainly had them, as I've already argued. And since we still find them scattered about among a great many indigenous peoples worldwide, it seems clear that HMP must also have had them.
Were HMP hunters and gatherers? An obvious question for many, but it must be asked, nevertheless. And since so many indigenous peoples in Asia, Oceania and the Americas are not strictly hunters and gatherers, but also, to some extent, farmers (more commonly referred to as "horticulturalists") this must remain an open question -- despite the widespread assumption among anthropologists and archaeologists that no form of farming or herding could have taken place prior to ca 10,000 years ago. I'm not so sure, so I'd prefer to leave this as an open question.
(to be continued . . . )
*While it's possible to argue, on the basis of its apparent late appearance in the Americas, that the bow and arrow may well have been independently invented there, it seems highly unlikely that it could have been independently invented in many different places, as is sometimes claimed. There is nothing obvious about bows and arrows, and certainly nothing obvious about the archery skills necessary if they are to be of any use. Given what we now know about African origins, it seems logical to conclude that a technology as widely used as this must have had its beginnings on that continent, along with so much else.
Monday, December 14, 2009
Looking more closely at Maju's tree, however (see Post 253), I see that M-derived haplogroups are found exclusively along the southern route [assuming East Asia was initially populated via Southeast Asia, as suggested in a recent publication]. It would appear to be only the N-derived haplogroups that are found along both routes. This suggests the following possibility: 1. an initial migration out of Africa by a group dominated by M haplotypes, whose descendants followed the southern coast of Asia pretty consistently from Yemen to Southeast Asia, Sundaland and the Sahul, with at least one subgroup pressing northward along the Pacific coast toward northeast Asia, Japan, Siberia and ultimately the Americas; 2. a second out of Africa migration by a group dominated by N haplotypes, which could have begun along the southerly route, but at some point bifurcated, possibly at what would have been the first major water obstacle, the Indus River Delta, with one group forging on along the southern route, and another continuing north along the west coast of the Indus to ultimately populate western India, Europe and Central Asia. Since Maju put this tree together, I'm wondering what he thinks of such a possibility.
Another possibility is a single exodus from Africa of groups dominated by L3 haplotypes, which bifurcated into M and N subgroups while in Asia, possibly at the same point, the Indus Delta. It's not clear, however, why all or most of the M groups would have continued along the southern route, with only the N groups bifurcating into northern and southern clades. Which leads me to believe that a dual exodus theory could make more sense. I'm wondering also whether the Y chromosome and autosomal evidence might either clarify or muddy the mtDNA picture.
I'm sorry to make such a fuss over what might seem like a purely technical issue that might never get resolved, but it's important to my project that we be able to determine whether one or two (or possibly more) groups migrated out of Africa during this very early period of human history. I believe the cultural evidence could provide us with some clues, but it would be really helpful to know more clearly what lies behind the sometimes puzzling and contradictory genetic evidence.
Sunday, December 13, 2009
Two very intriguing questions immediately come to mind: 1. is there any evidence that HMP were short, like today's Pygmies -- and also certain Bushmen groups; or is it more likely they were of "normal" size, or even taller? 2. is there any evidence that could help us decide whether HMP were morphologically closer to Pygmies or to Bushmen? I think there is evidence that could help us on both counts, though some of it is inconclusive for sure.
To deal with the "easy" question first, it seems evident that HMP must have been more Pygmy-like, 1. because there are a great many "negrito" peoples in South Asia, Southeast Asia, Indonesia, and Melanesia, who have a decidedly "pygmoid" physiognomy; 2. there are also a great many taller peoples who strongly resemble Bantu Africans, who are closely related genetically to African Pygmies and look far more like Pygmies than Bushmen; 3. no other people in the world look like Bushmen,* while a great many resemble African Pygmies; 4. the genetic evidence seems consistent with Pygmies, or at least proto-Pygmies as ancestral to everyone else, while mtDNA L0, characteristic of most Bushmen, seems relatively isolated, with no out of Africa branches at all. I'm aware, of course, that there are some striking similarities between modern East Asians and Bushmen, including the epicanthic fold, flattened facial features, etc., but I don't see any evidence of a direct or intermediate link between the two populations, so this might well be a coincidence -- (or perhaps the late "flowering" of some recessive genes).
As for shortness, this is a more complex issue, because we still don't know whether the shortness of all or even most Pygmy groups is inherited from a common ancestor or represents a series of independent adaptations. What we do know is that every single "negrito" group in the world is located along the hypothetical southern coastal route supposedly taken by HMP after leaving Africa for Asia, and it would seem difficult to explain the presence of so many of these groups -- many of which are hunter-gatherers with a culture very similar to HBC -- along this particular path unless they were direct descendants of HMP. It's also true, however, that many, though not all such groups were orginally found living in tropical forest environments, which means that all Pygmy and Pygmoid shortness could be an adaptation to that particular environment (though this doesn't explain Bushmen shortness). It's also true that the great majority of groups now living along this path, and represented by M and N clades, are not negritos. So if HMP were Pygmies, or Pygmoid, then why aren't all their descendants short? If we insist on a single Out of Africa migration, then, at some point, at least one of the descendant groups must have adapted, one way or the other. But this difference could also be the sign that there was more than one Out of Africa migration, and thus more than one HMP, one short, one of "normal" size. Do we need to think in terms of HMP1 and HMP2? and HMC1 and HMC2 as well? As we turn to the cultural evidence, we might find some clues to help us deal with this very fundamental question.
(to be continued . . . )
*[Added 12-14: I should have written "no other people in the world, outside of Africa, look like Bushmen." There are many people in southern Africa who do in fact look a lot like Bushmen, which is to be expected if we accept the commonly held theory that Bushmen and their close relatives, the Khoi-khoi (so-called Hottentots), dominated all or most of southern Africa prior to the Bantu expansion.]
Saturday, December 12, 2009
Despite the fact that N appears lower down on this map than M, it's important to recognize that both are "sister" clades, branching off from the same "mother": L3 -- now found only in Africa. If M and N are sisters, does this mean there were two different Out of Africa migrations? I don't know enough about population genetics to get into this question very deeply, but perhaps Maju, who knows a lot more than I, will be willing to chime in with some suggestions. I found an interesting reference to this issue in a paper by Luca Cavalli-Sforza and Marcus Feldman, The Application of Molecular Genetic Approaches to the Study of Human Evolution, dating from 2003.
Having established, however provisionally, a baseline for the consideration of the physical and cultural nature of the population ancestral to M, N, and L -- what I've been calling HBP and HBC -- we are now in a position to speculate further regarding the physical and cultural characteristics of their descendants, the Out of Africa migrants. This will not be anywhere near so easy, however. If you look carefully at the phylogenetic tree reproduced above, you'll notice an important difference between the uppermost branches, labeled L, and those lower down, dominated by M and N. Though not indicated on the diagram, the deepest branches, especially L0, L1, and L2, are dominated by Bushmen groups and both of the major Pygmy groups, Eastern and Western. The simplicity of this picture, along with the equally clear musical evidence, has made it relatively easy to characterize HBC on the basis of what we know about these three groups, using the triangulation method already described. The many branches emanating directly from M and N present a very different picture, however, with far less structure. Unlike the situation with L, it's not at all clear where we can look if we wish to triangulate, or even quadrangulate or quintangulate (have I just invented two new words?).
We can, of course, look backward to HBC for signs that certain ancestral features might have survived in HMC. But we will also need to draw on what we know about a great many indigenous societies in many different parts of Asia, Oceania, Australia and Europe as well. And since there are so many differences among so many of these groups, our task will not be easy. It is nevertheless, in my opinion, possible to develop some very interesting and to some extent testable hypotheses regarding both HMP and HMC, and to the extent that we can do so, we will have established another important baseline for the study of human history.
Friday, December 11, 2009
They had their picture taken, however, though it wasn't developed until tens of thousands of years later. Here it is:
It's a family picture. To enlarge it, right-click and select "Open in New Window." They're the ones roughly in the middle, toward the bottom, in the violet area, under the words "Out of Africa" -- the ones labeled M and N. This picture is somewhat misleading, however. First of all it's ladies only, the men have been excluded. Secondly, it's restricted only to surviving family members, or, to be more precise, those whose lineages have survived all the way to the 20th and 21st centuries. There were undoubtedly many others who could have been represented, some of whom might even have crossed over to Asia before them, but, most geneticists seem convinced that M and N are the only "Out of Africa" families whose lineages survived. Which means that everyone whose ancestors lived outside of Africa is descended from this one small group. The Migrants. What I'll be calling HMP, or "Hypothetical Migrant Population."
Thursday, December 10, 2009
What makes this a problem is that it isn't always so easy to distinguish the two. For example, the Encyclopedia includes a chapter on the Batak, in the Philippines, despite the fact that "they have long produced some rice by shifting cultivation, together with smaller amounts of maize, cassava and sweet potato, but cultivation is a far less important activity for them than it is for their lowland neighbors" (p. 295). I have a feeling that much the same could be said of a great many Melanesian "horticulturalists" as well.
In an online article, The Hunter-Gatherer Spectrum in New Guinea, Paul Roscoe informs us that some New Guinean populations are -- or were -- hunter-gatherers after all:
It has long been supposed that New Guinea is a land of cultivators. New Guineans were among the first peoples on Earth to cultivate crops, and at contact a majority were either horticulturalists, cultivating root crops such as taro and yam under long-fallow regimes, or agriculturalists cropping sweet potato under intensive cultivation regimes. However, a close examination of the ethnographic record – in particular, of unpublished and non-English language sources – has revealed numerous references to the presence of “hunters and gatherers.”
Roscoe distinguishes two principal types of New Guinea foragers:
Groups that procured limited amounts of meat protein or that relied primarily on terrestrial and arboreal game markedly resembled the classic hunter-gatherer societies typified by the Kung, Inuit, Mbuti, and many Australian Aboriginal groups. At contact, their population densities were usually below 1/sq.km; their settlements were small, typically between 10 and 40 inhabitants; and they were mostly semi- or fully-nomadic, shifting residence every few weeks or months. Political life was relatively egalitarian: inequities in power and influence
were uncommon, though fighting prowess, hunting ability, ritual expertise (including sorcery), and/or economic generosity brought prestige. Mobility was an important conflict resolution mechanism. Ritual life was comparatively unelaborated, and there was little visual art - though other aesthetic pursuits
such as dance and song were sometimes highly developed.
However: "Contradicting a common stereotype that war is attenuated or absent among hunters and gatherers, fighting was endemic." [my emphasis]
The other type of forager group concentrated on "aquatic resources" rather than terrestrial hunting and, interestingly enough, had a very different type of culture:
Groups that depended on aquatic resources rather than terrestrial and arboreal game typically exhibited a cultural complexity rivaling that of agriculturalists in New Guinea and they strongly resembled other aquatically adapted, hunter-gatherer societies such as the Native American communities of the Northwest Coast. . .
Most of these groups also had developed highly elaborate ceremonial and visual art. Some, such as the Asmat, Karawari, Kwoma, and Purari are among the most famous of New Guinea’s ritual artists.
And once again, as with the terrestrial foragers, violence is an important theme: "Warfare was generally intense, and most of these groups were head-hunters."
The importance of violence among New Guinea's hunter-gatherers, and in Melanesia generally, even among the simpler, more egalitarian societies, certainly does go against the stereotype, an "inconvenient truth" that must be accounted for by anyone seeking to characterize hunter-gatherers in general according to the "core values" we've been discussing.
The contradiction is not lost on Roscoe:
Hunter-gatherer scholarship has largely overlooked the importance of war, partly because of long-standing assumptions that warfare is a relatively recent emergence in human history and that hunter-gatherers lead a peaceful life. There is increasing evidence, however, that these assumptions are misplaced and that New Guinea’s foragers may more accurately represent the hunter-gatherer past. Recent primate research finds that chimpanzees practice a form of lethal aggression against neighbors that has striking similarities to ambush in human
society. This suggests that organized deadly violence may antedate the human-chimpanzee split, some 5 to 7 million years ago, and therefore may have characterized the whole of human prehistory. This conclusion is corroborated by historical research on reputedly peaceful hunter-gatherer groups such as the
!Kung, Inuit, and Australian Aborigines, which suggests that war was considerably more prevalent among these peoples than previously supposed.
Looks like deja vu all over again. I've already examined some of these issues in earlier posts, specifically the questionable comparison of humans with chimps (see Post 197), Steven Pinker's claim that early humans must have been "naturally" violent, based on all the "new" evidence of violence among hunter-gatherers (see Post 199), and the "revelation" that the so-called "Harmless People," i.e., the !Kung Bushmen, were at some point discovered to have an unusually high homicide rate (see Post 209).
Another complication posed by Melanesia, not mentioned by Roscoe, but of equal relevance, is the importance in just about every Melanesian society of the so-called "Big Man." According to Marshall Sahlins, who made an intensive study of Melanesian social structure,
Politics is in the main personal politicking in these Melanesian societies, and the size of a leader's faction as well as the extent of his renown are normally set by competition with other ambitious men. . .While Melanesian social structure is still often referred to as "relatively egalitarian" or "more-or-less egalitarian" (see for example "Irian Jaya - Anthropological and Historical Perspective," by Waruno Mahdi, part 2), the notion of a "Big-Man" in the above sense would be pure anathema to any of the Pygmy or Bushmen groups whose cultures we've been examining. These cultures are more than simply "egalitarian," they perpetuate social mechanisms that actively discourage any attempt on the part of any individual to stand out from the group. While certain individuals do emerge as what could be called "natural leaders" due to certain outstanding abilities, personal ambition is strongly frowned upon, and overt competition of any kind is almost unheard of.
[A Big Man] must be prepared to demonstrate that he possesses the kind of skills that command respect . . . Typically decisive is the deployment of one's skills and efforts in a certain direction: towards amassing goods, most often pigs, shell monies and vegetable foods, and distributing them in ways which build a name for cavalier generosity, if not for compassion (Poor Man, Rich Man, Big Man, Chief, pp. 290-291).
It's important to understand that neither violence nor "Big-Man" politics among hunter-gatherers, or horticulturalists with otherwise very similar cultures, is by no means confined to Melanesia, though both are particularly common in this region. In fact there are many such groups that have exhibited highly competitive and violent behavior, in many parts of the world.
So what gives? Does this mean that "deadly violence" in fact "characterized the whole of human prehistory," as Roscoe, and so many others, have alleged (see above)? Does it mean that the spirit of competition is ingrained into the human spirit, in the now widely accepted "liberal" view dominating "free" market economics? Only if we are willing to accept the commonly held view of "hunter-gatherers" as represenative, for better (the traditionalist view) or worse (the revisionist view), of some sort of universalized essence of "Stone-Age Man."
As I made clear in the previous post, I cannot accept such a view, from either perspective (i.e., "naturally" egalitarian and non-violent or "naturally" competitive and warlike), because neither makes sense and both are based on assumptions rather than evidence. As now seems clear, from both the genetic and the cultural evidence, all such groups, along with all other human societies now sharing our planet, are descended from a single ancestral group that could only have had a very particular culture, which I've been calling HBC.
And if the ancestral culture can be modeled, as I believe it can, on the "fiercely egalitarian" (Barry Hewlett, Intimate Fathers), non-competetive, and essentially non-violent* ("War is unknown," William L. Ury, Conflict Resolution among the Bushmen) ethos of Pygmy and Bushmen hunter-gatherers, then I'm sorry but no: neither "deadly violence" nor the competitive spirit "characterized the whole of human prehistory." While some "hunter-gatherers" can undoubtedly be described in such terms, the ancestral group from which they emerged was, in all likelihood, relatively egalitarian and peaceful.
What could have happened among so many of their descendants that turned them so disastrously in the direction of both competiveness and war?
*See Post 209 for an in-depth discussion of Bushmen violence. While acts of violence, including murder, have been reported among both Pygmies and Bushmen, the core values reported over and over again for all these groups strongly discourage violent behavior, there is no glorification of war or warriors, and in fact no warrior class at all -- nor are there any weapons of war, nor any sign of the blood feuds, raids and out and out warfare so common among the groups discussed above.