I have heard this refrain quite often, that Brahmins are close to Eurasian DNA than the NB population of India.
As far as I have read on DNA oriented forums and papers, it's more of a West Eurasian equivalent.
West Eurasian can be considered the genetic entity of the Caucasoid race, of course.
Quite often people make this claim with a dash of superiority thrown in. It is indeed surprising that closeness to a population that produced Genghis Khan and Timur is a matter of pride.
A little misunderstanding there buddy? Timur and Genghis Khan are Central Asians. When the AIT/AMT said we came from Central Asia, it did'nt mean our ancestors looked like the present day inhabitants, who honestly genetically and phenotypically seem to be like the Turkics, a Caucasian-Mongoloid hybrid peoples.
Yes, it is said with pride among Brahmin, you are right. We claim our 'Aryan blood' from our paternal lineage.
Be that as it may, are the Brahmins much more closely related to foreigners? Are they descendants of an invading hoard of Aryans? Does this mean these Brahnmins take AIT to be a fact? Oh, well, I will leave it to them to answer these questions. But let us look at the central claim of DNA proximity itself.
For the most parts Brahmins are more related to North Indians. That's all there is to it. Any self-respecting caste, especially like us Brahmins would not claim a foreign origin, atleast we wouldnt go as far as some Pakistanis seem to go, all this 'Scythian' and this other nonsense. Brahmins expanded from what is now Pakistan/North West India i.e Ancient Indus Valley to other parts of the sub continent. In truth we are the original definition of the word 'diaspora'.
It is undeniable through our gotrams/family names,etc we will ultimately trace our lineage back to those areas.
Sometime back HappyHindu gave a list of journal articles that addressed this question. One of those articles presented evidence that there was more homogeneity of DNA markers between certain Brahmin clusters and Adivasees in Maharashtra (?) than between different Brahmin populations.
Brahmins everywhere are more related to each other than they are to the general population. Be it the customs, culture, religion or as it is in question now, DNA.
There was another article that suggested, and I quote,
"The upper caste Brahmins and Muslims were closest to Caucasians while middle caste populations were closer to Asians"
-- click here for the article
But this is only half the story. The other half of this story is found in another article,and I quote from this one,
"although the Y-chromosome data show that the genetic distances of populations are not correlated to their position in the caste hierarchy"
-- Click here for this article
So, this tells us that all our mothers came from the same indigenous population in the same proportion among all castes, but among the the population studied, the proportion of fathers from indigenous population was lower among Brahmins and Muslims. So, Brahmins and Muslims have a larger proportion of fathers who are of later arrivals, who may have come from central Asia starting from about 50,000 years to as late as 3000 years ago. All this shows is that we all are mongrels and mutts, and, perhaps the so called upper castes and Muslims are more so than the "lower" castes.
It is the general concensus that higher/twice born castes are significantly more related to West Eurasian groups and lower castes of South and the East of India more related to Eastern Eurasian groups. The lower castes of Northern (West) India are itself significantly West Eurasian by genes it seems.
There may be a 1000 claims back and forth. Yet, from the evidence discovered so far we can safely say we all are thoroughly mixed up, we are all mongrels and mutts and let us enjoy life as they do without getting caught up on how much of what DNA we have.
Yes, Tamil Brahmins are mixed. But to be a Brahmin you have to have a Brahmin father. Ours is a patriarchal society so as to speak, so we claim our lineage through our paternal line. Any intermixing with the locals is mostly maternal, as reveals our DNA too..
Our northern counterparts, on the other hand are fully West Eurasian, both maternally and paternally. This is the only difference between us and them.