Tag Archives: brahui

Brahui are something old, not new

Posted by on July 3, 2011 15 comments

From Wikipedia:

The ethnonym "Brahui" is a very old term and a purely Dravidian one. The fact that other Dravidian languages only exist further south in India has led to several specualations about the orgins of the Brahui. There are three hypotheses regarding the Brahui that have been proposed by academics. One theory is that the Brahui as a relic population of Dravidians, surrounded by speakers of Indo-Iranian languages, remaining from a time when Dravidian was more widespread. Another theory is that they migrated to Baluchistan from inner India during the early Muslim period of the 13th or 14th centuries. More established theory says the Brahui migrated to Balochistan from central India after 1000 CE. The absence of any older Iranian (Avestan) influence in Brahui supports this hypothesis. The main Iranian contributor to Brahui vocabulary is a western Iranian language like Kurdish.

A lot of ADMIXTURE plots I've seen are more consistent with the first (indigenous) than the latter two (exogenous) models. Here's a result for K = 9 with ~90,000 markers:

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HGDP

Posted by on January 25, 2011 3 comments

Human Genome Diversity Project (HGDP) is the best resource for a diverse set of genomic data. It has 1050 individuals from 52 different populations.

I got the Stanford University data which has data for 660,918 SNPs from 1,043 samples. It is claimed that the forward strand is given but that turned out not to be true and I had to flip strands and make sure I didn't include any ambiguous A/T or C/G strands in my dataset.

I followed the recommendations of Rosenberg (spreadsheet) in excluding some atypical samples and relatives, leaving me with 940 samples.

I also excluded the Native American samples because we are not interested in them and they are very closely related either due to recent endogamy or ancient bottlenecks. (yeah I had the nerve to write that.)

Of the total of 876 samples, here are the numbers for our populations of interest:

Balochi 24
Brahui 25
Burusho 25
Hazara 22
Kalash 23
Makrani 25
Pathan 22
Sindhi 24
Total South Asians 190

These samples have about 541,560 SNPs in common with 23andme v2.