Tuesday, December 28, 2010

The Origin of Y-chromosome Haplogroup J1: Another Lake, Other Rivers

What a surprising story the J1e haplogroup tells.  Thanks to the work of Chiaroni et al (1), Sengupta et al (2005)  and El-Sibai et al (2), we have detailed spatial frequency distribution maps of the J1 and J2 y-chromosome haplogroups.  Chiaroni et al, with their detailed samplings of the Lake Van and Greater Zab River areas, also pinpoint the region of greatest J1e and J1* variance spatial distribution.  Table 1 of the Chiaroni paper describes expansion times, mean YSTR variance and archaeological correlates for all of their sampled populations.  Three populations are boldface standouts:  Alawites of coastal Syria with a mean J1e YSTR variance of 0.37 and an expansion time of 16.1 kya (SD 4.5 kya), Assyrians (Northern Syria, Northern Iraq, Lake Van and Urmia in Iran) with a mean J1e YSTR variance of 0.43 and an expansion time of 16.2 kya (SD 6.4 kya) and J1* Turks with a J1* expansion time of 20 kya (SD 7.5 kya).

Figure 1 results in the paper are vivid:

"(a) Red symbols indicate the geographical locations of 36 populations analyzed. (b) Interpolated spatial contours of annual precipitation (mm) distribution. (c) Interpolated J1* frequency spatial distribution. (d) Interpolated J1e frequency spatial distribution. (e) Interpolated J1e mean haplotype variance spatial distribution. (f) Construed trajectories of J1e lineage spread episodes. In red are delineated the initial Holocene migrations from the Taurus/Zagros Mountains to the Arabian Peninsula. Shown with black arrows are the subsequent expansions of Arabic populations in Arabia beginning in the Bronze Age."

Figure 1c and 1e are highly suggestive of a J1*-J1e origin in the Lake Van region of Turkey.  It is notable that Lake Van lies at the nexus of the Aras and Tigris Rivers which I have described in previous posts Rivers, Lakes and Mountains and Northern Fertile Crescent Hunter Gatherers.  According to Figure 1f, the expansion trajectory of J1e between 11 and 8 kya is threefold:  southwestward to what appears to be the Orontes River in Syria, southward to the Arabian peninsula and southeastward along the Greater Zab and Tigris Rivers.

Lake Van and the Greater Zab River present a beautiful if windswept picture.  No doubt, the climate during the Mesolithic period was even colder and dryer in this region than it is today.  The Mesolithic ancestors of J1 must have been an inventive and resourceful people to have survived:

The Akhtamar Island in Lake Van with the 10th century Armenian Cathedral of the Holy Cross

As Table 1 notes, the J1e ancestors of the Assyrians of Lake Van and the Greater Zab River, as well as J1* Turks of Lake Van, originate from a common ancestor some 16 kya.  Zagros archaeological results for this period, known as the Zarzian, are at the cutting edge of current research and are giving us some idea of the lifestyle of these Mesolithic people (references 3, 4 and 5).  A map illustrates the region of the Zarzian Mesolithic:

Geometric Kebaran 16,000BC-12,500BC calibrated (Radiocarbon Context Database (Link))

I will note also that the Zarzian Mesolithic region shows a surprising correspondence with the LBK Derenberg graveyard genetic analysis (Haak et al):

Figure 3A and 3B
"Mapped genetic distances are illustrated between 55 modern Western Eurasian populations and the total of 42 Neolithic LBK samples (A) or the single graveyard of Derenburg (B). Black dots denote the location of modern-day populations used in the analysis. The coloring indicates the degree of similarity of the modern local population(s) with the Neolithic sample set: short distances (greatest similarity) are marked by dark green and long distances (greatest dissimilarity) by orange, with fainter colors in between the extremes. Note that green intervals are scaled by genetic distance values of 0.02, with increasingly larger intervals towards the “orange” end of the scale."

This leads me to wonder if further analysis of  the Derenburg LBK y-DNA would yield J1* and J1e y-chromosome haplogroups.  The Assyrians sampled in the Chiaroni paper showed the highest J1e variance but also have a G y-chromozome haplogroup correlation which corresponds with the y-chromosome results at Derenburg.

Other results emerge from the Chiaroni et al and El-Sibai et al papers.  A clear split appears in the expansion pattern between the J1 and J2 y-haplogroups:  The J1 expansion is associated with pastoralism;  J2 demonstrates a coastal agriculture expansion pattern.

In keeping with my post on The Bedouin, both papers also support the notion of an expansion of J1e onto the Arabian peninsula, followed by an exodus from the Central Arabian peninsula approximately 6000 years ago with the cessation of Indian Ocean Monsoon induced rains.



References

(1)  Chiaroni et al;  The emergence of Y-chromosome haplogroup J1e among Arabic-speaking populations (Link)

(2)  El-Sibai et al;  Geographical Structure of the Y-chromosome Genetic Landscape of the Levant:  A coastal-inland contrast (Link)

(3)  The Central Zagros Archaeological Project Biblographic Reference List (Link)

(4)  Solecki, Ralph S.; Rose L. Solecki, Anagnostis Agelarakis; The Proto Neolithic Grave at Shanidar Cave (Book), Texas A&M University Anthropology Series

(5) Peasnall, B; Iranian Mesolithic in Encyclopedia of Prehistory:  South and Southwest Asia, Volume 8, University of Pennsylvania Museum Near East Section, pp. 205-214.
(Link)