October 08, 2012

rolloff analysis of North Indian Brahmins as Orcadian+North Kannadi

In a previous experiment, I tested the Dodecad Project South Indian Brahmin sample (Iyer and Iyengar) using Orcadians and North Kannadi as reference populations. In the current one, I use the same references to investigate admixture in the Uttar Pradesh Brahmins included in the Metspalu et al. (2011) dataset. A total of 473,837 SNPs are used in this experiment.

I first verified that f3(Brahmins_from_Uttar_Pradesh_M; Orcadian, North_Kannadi) is negative, using qp3Pop:
 Source 1 Source 2 Target f_3 std. err Z SNPs
 result: Orcadian North_Kannadi Brahmins_from_Uttar_Pradesh_M -0.007882 0.000359 -21.951 463297

The exponential fit can be seen below:
The estimated age is 79.706 +/- 9.197 generations, or 2,310 +/- 270 years.

This is about a thousand years younger than the signal observed for the South Indian Brahmin group. A possible explanation has to do with the fact that South Indian Brahmins migrated to South India, and hence did not intermarry with successive waves of invaders into India in historical times. Uttar Pradesh, on the other hand, received multiple invasions from the direction of Central Asia:
Most of the invaders of North India passed through the Gangetic plains of what is today Uttar Pradesh. Control over this region was of vital importance to the power and stability of all of India's major empires, including the Maurya (320–200 BC), Kushan (100–250 CE), Gupta (350–600 CE), and Gurjara-Pratihara (650–1036 CE) empires.[11] Following the Huns invasions that broke the Gupta empire, the Ganges-Yamuna Doab saw the rise of Kannauj.[12] During the reign of Harshavardhana (590–647 CE), the Kannauj empire reached its zenith.[12]
It will be interesting to see whether a young admixture signal also exists in my 5-strong sample of Jatts, since that population has traditions of "Scythian" origins.

5 comments:

terryt said...

"A possible explanation has to do with the fact that South Indian Brahmins migrated to South India, and hence did not intermarry with successive waves of invaders into India in historical times".

Makes complete sense.

"Most of the invaders of North India passed through the Gangetic plains of what is today Uttar Pradesh".

And probably true during the Paleolithic as well. Goodbye southern coastal migration theory. Finally, I hope.

SB said...

Dienekes,
I doubt ""A possible explanation has to do with the fact that South Indian Brahmins migrated to South India, and hence did not intermarry with successive waves of invaders into India in historical times".
is the explanation for this.
Historical evidence points to the fact that south Indian brahmins moved from the areas of the "Narmada River" (and probably north of it) to India in many waves. The latest(and probably the largest) was as early as the 8th to 11th century C.E during the Muslim invasion of North India and destruction of Temples. South Indian kings patronized these Brahmins. I think what you are seeing is probably the result of Brahmins inter marrying with South Indians since then.
It is true that during ancient history, many groups that migrated to India were assigned different "castes". But this system probably solidified more than 2000 years ago after which new populations were considered "Mlecchas". Case in point, the Jatts technically do not belong to the caste system, probably because they were one of the later groups to migrate.
I think a different explanation needs to be looked at for the age discrepancy.

Dienekes said...

I think what you are seeing is probably the result of Brahmins inter marrying with South Indians since then.

Why would Brahmins intermarrying with Sound Indians in the last ~1,000 years cause south Indian Brahmins to show an earlier signal of admixture than north Indian Brahmins?

SB said...

Could it be because the south Indians they intermarried with, themselves had earlier signal of admixture? I don't know... I was only alluding to the historic aspects on the topic. But then historical records may not reflect reality...

Nirjhar007 said...

''Most of the invaders of North India passed through the Gangetic plains of what is today Uttar Pradesh. Control over this region was of vital importance to the power and stability of all of India's major empires, including the Maurya (320–200 BC), Kushan (100–250 CE), Gupta (350–600 CE), and Gurjara-Pratihara (650–1036 CE) empires.[11] Following the Huns invasions that broke the Gupta empire, the Ganges-Yamuna Doab saw the rise of Kannauj.[12] During the reign of Harshavardhana (590–647 CE), the Kannauj empire reached its zenith.[12]''
Two things-
1.the results suggest; north indian brahmins are less of a pure brahmin group compared to of south, a thing that the ni brahmins will not like.
2.so recent admixtures can make a population look younger.