to Australia: Evidence from the Y Chromosome, by Alan Redd et al., 2002, the authors present "strong evidence for an influx of Y chromosomes from the Indian subcontinent to Australia . . . " (the Y chromosome is found only in males and can represent only male lineages):
In sum, we found that 50% of the Y chromosomes sampled from aboriginal Australians share common ancestry with a set of Y chromosomes that represent less than 2% of the sampled Indian subcontinent paternal gene pool. The similarity among C* chromosomes is unlikely to have been caused by chance convergence because we genotyped ten independent STRs. The observed pattern is not specific to central Australians, since our sample also included individuals from the Great Sandy Desert and from Western Australia, and our estimate of the frequency of C* chromosomes agrees remarkably well with other studies of greater numbers of aboriginal Australian Y chromosomes in Arnhem Land, the Great Sandy Desert, the Kimberleys, and the Northern Territory. (676 -- my emphasis).
Figure 2 from this paper represents the worldwide distribution of Y haplogroup (hg) C:
The segments in red represent subhaplogroup C* (or C root), which was the focus of this study. Remarkably, one can trace the migration of C* from its first appearances, in south India and Sri Lanka (SRL), through Southeast Asia (SEA) and East Indonesia (EIN) to the Australia Aboriginal People (AAP), where it is present in fully half the male population sampled.
Background: An early dispersal of biologically and behaviorally modern humans from their African origins to Australia, by at least 45 thousand years via southern Asia has been suggested by studies based on morphology, archaeology and genetics. However, mtDNA lineages sampled so far from south Asia, eastern Asia and Australasia show non-overlapping distributions of haplogroups within pan Eurasian M and N macrohaplogroups. Likewise, support from the archaeology is still ambiguous.Results: In our completely sequenced 966-mitochondrial genomes from 26 relic tribes of India, we have identified seven genomes, which share two synonymous polymorphisms with the M42 haplogroup, which is specific to Australian Aborigines.Conclusion: Our results showing a shared mtDNA lineage between Indians and Australian Aborigines provides direct genetic evidence of an early colonization of Australia through south Asia, following the "southern route".
Stephen Oppenheimer writes as follows of the Chenchu, in connection with the M2 haplogroup and its possible relation to the Toba eruption:
The eldest of [the] many daughters [of haplogroup M] in India, M2, even dates to 73,000 years ago. Although the date for the M2 expansion is not precise, it might reflect a local recovery of the population after the extinction that followed the eruption of Toba 74,000 years ago. M2 is strongly represented in the Chenchu hunter-gatherer Australoid tribal populations of Andhra Pradesh, who have their own unique local M2 variants as well as having common ancestors with M2 types found in the rest of India. Overall, these are strong reasons for placing M’s birth in India rather than further west or even in Africa.(to be continued . . . )