Thursday, January 6, 2011

Embarking on an Exploration of the E Haplogroup Dispersal with relation to ADMIXTURE

Egyptian men relaxing outside ahwa (coffee house) (Link)

It's been over a month since I first posted the Eurogenes ADMIXTURE results for Middle Eastern populations. (Link)

As some of you might remember, I took the Eurogenes ADMIXTURE results and normalized them on three components, the West Asian, Southwest Asian and South European components:

Populations are Georgian, Iranian, Armenian, Uzbekistan Jews, Azerbaijani Jews, Georgian Jews, Iranian Jews, Iraqi Jews, Druze, Syrians, Jordanians, Palestinians, Samaritans, Egyptians, Yemenis, Saudis, Bedouin

Working from these plots, I've been focusing on the association between haplogroups and these three ADMIXTURE components.  Up to now, I've focused primarily on haplogroups that are confined to West Asia and Southwest Asia.

What of the South European component?  With what haplogroups is it associated?
There are several clues:  the component is slightly elevated in Cypriots and Egyptians while being suppressed in Saudi Arabia and the Bedouin.  It's quite suppressed in coastal Pakistan and India.

Haplogroup E-M78 is prevalent in the Coastal Mediterranean, including Cyprus and Egypt (El-Sibai), while being absent from India (Sengupta).

Following the likelihood grouping pattern discussed earlier, ADMIXTURE probably lumps several other haplogroups into the South European component, but for West Asia and North Africa, it is E-M78 that presents the most distinctive and dominant pattern.

During the last ten years, the investigation of the E haplogroup has not been an easy one and its description in ISOGG only begins to touch upon the complexity of its distribution and the conjecture as to its origin.

As an E-M78 starting point, I reference Cruciani 2007, below.   A number of subsequent papers further define the origin and dispersal of the E Haplogroup.  Over the next few days, I'll be reviewing those papers and posting as appropriate.

Tracing Past Human Male Movements in Northern/Eastern Africa and Western Eurasia:  New Clues from Y-Chromosome Haplogroup E-M78 and J-M12
Cruciani et al
(Link)

Abstract: 

Detailed population data were obtained on the distribution of novel biallelic markers that finely dissect the human Ychromosome haplogroup E-M78. Among 6,501 Y chromosomes sampled in 81 human populations worldwide, we found 517 E-M78 chromosomes and assigned them to 10 subhaplogroups. Eleven microsatellite loci were used to further evaluate subhaplogroup internal diversification. 

The geographic and quantitative analyses of haplogroup and microsatellite diversity is strongly suggestive of a northeastern African origin of E-M78, with a corridor for bidirectional migrations between northeastern and eastern Africa (at least 2 episodes between 23.9–17.3 ky and 18.0–5.9 ky ago), trans-Mediterranean migrations directly from northern Africa to Europe (mainly in the last 13.0 ky), and flow from northeastern Africa to western Asia between 20.0 and 6.8 ky ago. 

A single clade within E-M78 (E-V13) highlights a range expansion in the Bronze Age of southeastern Europe, which is also detected by haplogroup J-M12. Phylogeography pattern of molecular radiation and coalescence estimates for both haplogroups are similar and reveal that the genetic landscape of this region is, to a large extent, the consequence of a recent population growth in situ rather than the result of a mere flow of western Asian migrants in the early Neolithic.

Our results not only provide a refinement of previous evolutionary hypotheses but also well-defined time frames for past human movements both in northern/eastern Africa and western Eurasia.

2 comments:

  1. E-M78 may not be a good "starting point"
    It may be best to go start back at 2000-2002 with older Cruciani, Semino, and Underhill data. Seeing the distribution and spread of E from the root or at least from E1b1* (Pn2) really puts things in perspective.

    ReplyDelete
  2. Thanks. I'll back up to those early papers. Much appreciated.

    ReplyDelete

Comments have temporarily been turned off. Because I currently have a heavy workload, I do not feel that I can do an acceptable job as moderator. Thanks for your understanding.

Note: Only a member of this blog may post a comment.