Welcome Guest [Log In] [Register]
Add Reply
Y-chromosomes age (South Asia)
Topic Started: Dec 28 2005, 04:16:09 AM (655 Views)
Ibra
Global Mod
[ *  *  * ]
Polarity and Temporality of High Resolution Y-chromosome Distributions in India Identify Both Indigenous and Exogenous Expansions and Reveal Minor Genetic Influence of Central Asian Pastoralists

Sanghamitra Sengupta, Lev A. Zhivotovsky, Roy King, S. Q. Mehdi, Christopher A. Edmonds, Cheryl-Emiliane T. Chow, Alice A. Lin, Mitashree Mitra, Samir K. Sil, A. Ramesh, M.V. Usha Rani, Chitra M. Thakur, L. Luca Cavalli-Sforza, Partha P. Majumder and Peter A. Underhill

Abstract:

While considerable cultural impact on social hierarchy and language in south Asia is attributable to the arrival of nomadic Central Asian pastoralists, genetic data (mitochondrial and Y chromosomal) have yielded dramatically conflicting inferences on the genetic origins of tribes and castes of south Asia. We sought to resolve this conflict using high-resolution data on 69 informative Y-chromosome binary markers and 10 microsatellite markers from a large set of geographically, socially and linguistically representative ethnic groups of south Asia. We have found that the influence of Central Asia on the pre-existing gene pool was minor. The ages of accumulated microsatellite variation in the majority of Indian haplogroups exceed 10-15 kya, attesting to the antiquity of regional differentiation. Therefore, our data do not support models that invoke a pronounced recent genetic input from central Asia to explain the observed genetic variation in south Asia. R1a1 and R2 haplogroups indicate demographic complexity that is inconsistent with a recent single history. Associated microsatellite analyses of the high frequency R1a1 haplogroup chromosomes indicate independent recent histories of the Indus valley and the peninsular Indian region. Our data are also more consistent with a peninsular origin of Dravidian speakers than a source with proximity to the Indus and significant genetic input resulting from demic diffusion associated with agriculture. Our results underscore the importance of marker ascertainment towards distinguishing phylogenetic terminal branches from basal nodes when attributing ancestral composition and temporality to either indigenous or exogenous sources. Our reappraisal indicates that pre-Holocene and Holocene era not Indo-European expansions have shaped the distinctive south Asian Y-chromosome landscape.


Offline Profile Quote Post Goto Top
 
ren
Advanced Member
[ *  *  * ]
Yeah, C in another study was younger too, perhaps further east? Dunno. Really haven't kept up with anything for the last 50 days. It might have developed after F, which would be contrary to earlier assertions such as by Wells, right?

Can you link it and cite it?
Offline Profile Quote Post Goto Top
 
Ibra
Global Mod
[ *  *  * ]
Major points from the study:

- 80% of the Indian C* chromosomes, belonged to the newly defined C-M356 or C5.

-The Indian C5 chromosome doesn’t correspond to the Australian DYS390.1 deletion, so a mid Holocene migration for India to Australia can be ruled out.

-R2, R1a and L1 were shown to be indigenous

-Haplogroup H1 (26%) is the most frequent Y-chromosome in the South Asian gene pool.

-The Dravidian speakers originated in South West India along with their main haplogroup L1.

-The age of R1a in India is 14000 ypb, with the tribes having the greatest diversity of this haplogroup. Also, R1a falls into two clusters, one that West Eurasians have, and another that Indians and tribes have.

-There seems to have been a major expansion 10000-14,000 years ago of a population carrying H1, R1a, L1 and R2 across the Indian subcontinent.
Offline Profile Quote Post Goto Top
 
Ibra
Global Mod
[ *  *  * ]
Ages of South Asian haplogroup:

Posted Image

along, with their frequency,

http://tinypic.com/j9bnmw.jpg




Offline Profile Quote Post Goto Top
 
Ibra
Global Mod
[ *  *  * ]
Quote:
 
Yeah, C in another study was younger too, perhaps further east? Dunno. Really haven't kept up with anything for the last 50 days. It might have developed after F, which would be contrary to earlier assertions such as by Wells, right?


The C in question is the newly defined C5, which constitute 80% of Indian C chromosomes. Even though the C5 is only 20,000 years, the original C* must have been much older. Ren, I’ve never seen a clear estimate for C, do you have a possible date?

H-M69 is Palaeolithic in nature, as it is the oldest. The age of H and F, and F’s residual presence in Tribes, makes it likely that H arose in situ from F. The authors maintain this scenario, as well. They also defined an F2 haplogroup found at low frequency in Mongoloid Indians, as well as some Q haplogroups. I’m interested to know where else these haplogroups is found.

Dienekes bogged on this paper, some time back. The paper is massive and crammed with new information. Extracting all the information out of the paper is no cakewalk.

http://dienekes.blogspot.com/2005/11/new-p...chromosome.html
Offline Profile Quote Post Goto Top
 
ren
Advanced Member
[ *  *  * ]
I think I can get access to the full PDF..
Hey, the findings are consistent with what I've been saying.. when Dienekes kept telling me to "read before you say idiotic things like that". :rolleyes:
And now he's following along the same conclusions on his blog.

No complaints from me. :rolleyes:

Quote:
 
Ren, I’ve never seen a clear estimate for C, do you have a possible date?

I saw one date for C in another PDF black man provided. Hold on. I'll try to find it.

For M130, which pretty much equates to the entirety of C, page 13 of PDF:
http://www.pop.upenn.edu/news/colloquium/2...churr2002AR.pdf

M89/F is oldest at ~60 KYA, followed by M1 (Yap?) and M9 at 50 KYA and M130 is 30 KYA.
Offline Profile Quote Post Goto Top
 
Ibra
Global Mod
[ *  *  * ]
I read it when it was in the pre-Print version, ever since the break, I didn't have the means to access the full version.
Offline Profile Quote Post Goto Top
 
Ibra
Global Mod
[ *  *  * ]
Thanks for the link. Between 25,000 years and 30,000 years they say. It would be surprising if more calculations showed C to be younger than the other Eurasian haplogroups F, K and D.
Offline Profile Quote Post Goto Top
 
Ibra
Global Mod
[ *  *  * ]
A prehistory of Indian Y chromosomes: Evaluating demic diffusion scenarios

Sanghamitra Sahoo et al.

Understanding the genetic origins and demographic history of Indian populations is important both for questions concerning the early settlement of Eurasia and more recent events, including the appearance of Indo-Aryan languages and settled agriculture in the subcontinent. Although there is general agreement that Indian caste and tribal populations share a common late Pleistocene maternal ancestry in India, some studies of the Y-chromosome markers have suggested a recent, substantial incursion from Central or West Eurasia. To investigate the origin of paternal lineages of Indian populations, 936 Y chromosomes, representing 32 tribal and 45 caste groups from all four major linguistic groups of India, were analyzed for 38 single-nucleotide polymorphic markers. Phylogeography of the major Y-chromosomal haplogroups in India, genetic distance, and admixture analyses all indicate that the recent external contribution to Dravidian- and Hindi-speaking caste groups has been low. The sharing of some Y-chromosomal haplogroups between Indian and Central Asian populations is most parsimoniously explained by a deep, common ancestry between the two regions, with diffusion of some Indian-specific lineages northward. The Y-chromosomal data consistently suggest a largely South Asian origin for Indian caste communities and therefore argue against any major influx, from regions north and west of India, of people associated either with the development of agriculture or the spread of the Indo-Aryan language family. The dyadic Y-chromosome composition of Tibeto-Burman speakers of India, however, can be attributed to a recent demographic process, which appears to have absorbed and overlain populations who previously spoke Austro-Asiatic languages.

Offline Profile Quote Post Goto Top
 
Ibra
Global Mod
[ *  *  * ]
Again the Indigenous nature of Y-chromosomes like R2, R1a, L1 and H are confirmed once again contradiction the conclusions previous authors whose implications were true, but premises were false.
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
« Previous Topic · Y-chromosome: CF · Next Topic »
Add Reply