Afghanistan was one of those potentially key crossroads with only indirect sampling, mostly via ethnic relatives from Pakistan. Therefore we must welcome with a great applause the following paper, which fills a gap in our knowledge (next Burma, please):
Marc Haber et al., Afghanistan's Ethnic Groups Share a Y-Chromosomal Heritage Structured by Historical Events. PLoS ONE 2012. Open access.
Afghanistan has held a strategic position throughout history. It has been inhabited since the Paleolithic and later became a crossroad for expanding civilizations and empires. Afghanistan's location, history, and diverse ethnic groups present a unique opportunity to explore how nations and ethnic groups emerged, and how major cultural evolutions and technological developments in human history have influenced modern population structures. In this study we have analyzed, for the first time, the four major ethnic groups in present-day Afghanistan: Hazara, Pashtun, Tajik, and Uzbek, using 52 binary markers and 19 short tandem repeats on the non-recombinant segment of the Y-chromosome. A total of 204 Afghan samples were investigated along with more than 8,500 samples from surrounding populations important to Afghanistan's history through migrations and conquests, including Iranians, Greeks, Indians, Middle Easterners, East Europeans, and East Asians. Our results suggest that all current Afghans largely share a heritage derived from a common unstructured ancestral population that could have emerged during the Neolithic revolution and the formation of the first farming communities. Our results also indicate that inter-Afghan differentiation started during the Bronze Age, probably driven by the formation of the first civilizations in the region. Later migrations and invasions into the region have been assimilated differentially among the ethnic groups, increasing inter-population genetic differences, and giving the Afghans a unique genetic diversity in Central Asia.
|Fig. 1 - PCA derived from Y-chromosomal haplogroup frequencies|
In my understanding the really interesting stuff is in the supplemental table 4, which lists all the tested haplogroups for the Afghan samples.
Large and medium samples (n>10) simplified (only largest haplogroups):
- Hazara (n=60): 20 C3 (33%), 10 J2a* (17%), 6 J2a5 (10%), 4 R1a1a (7%), 3 B (5%), 3 E1b1b1c1 (5%),
- Tajik (n=56): 17 R1a1a (30%) 9 J2a (14%), 5 O (9%), 3 H1a (5%)
- Pashtun (n=49): 25 R1a1a (51%), 9 Q (18%), 6 L1c (12%), 3 G2c(6%)
- Uzbek (n=17): 7 C3 (41%), 3 R1a1a (18%), 2 R1b1a2 (12%)
- Baluch (n=13): 8 L1a (61%), 2 R2a (15%)
Small and tiny samples (n<10):
- Norestani (n=5): 3 R1a1a, 1 R2a, 1 J2a*
- Arab (n=3): 2 L1a, 1 R2a
- Turkmen (n=1): 1 R1a1a
Hazara Y-DNA oddities (B and M1)
|The Hazara Country (source) is the center of Afghanistan|
I must say that what stroke me the most were the three Y-DNA B Hazaras. This is a lineage almost unreported in Eurasia and much less in a population that shows no other signs of African admixture.
Supplementary table 1 lists all haplotypes and the three Y-DNA B Hazaras (two from Bamiyan and one from Ghor) have some differences: they are not recent relatives by patrilineage. Whenever the African lineage arrived to the area, it had since then some time to evolve and diverge locally.
Are we before yet another puzzling Out-of-Africa remnant like the East Asian Y-DNA DE (mostly D)? Or is something more recently arrived? If so, how did it reach such high frequencies among the Hazara (and only them)?
The Hazara sample also includes an individual with Y-DNA M1, which is in principle a Melanesian lineage, i.e. another haplogroup which should not be there, but this one from the opposite corner of the Old World.
Otherwise it seems evident that Y-DNA R1a1a dominates among Indoeuropean speakers (Pashtun, Tajik and Noristani), C3 among the Uzbek and Hazara and L1a among the Baluch and "Arab" (who seem identical to the Baluch).
J2a (maybe a Neolithic layer) is also important among Tayik and Hazaras, while Q is very important among Pashtuns (Q is most basally diverse in West Asia, in case you do not know, even if it is most frequent among Native Americans).