According to the historical data, the split between two sub-clans of the Kereys occurred about 20-22 generations ago (Khalidullin 2005). Estimation of divergence time (TD) of two groups of 15 STR haplotypes (except for DYS385a,b loci) found in the Kereys sub-clans demonstrates that TD value equal to 630 ± 190 years (or approximately 21 ± 6 generations) is resulted when a mean of per-locus, per-generation mutation rate of 0.0033 and a 30-year generation time are used. Note that similar value of mutation rate (0.00324) has been calculated as optimal for 15 STR haplotypes by Busby et al. (2011) who have investigated the question on how average squared distance (ASD) estimates change within haplotype sets when using different combinations of Y-chromosome STRs. This mutation rate belongs to a class of so called genealogical STR mutation rates revealed by direct observation in father/son pairs (Kayser et al. 2000; Goedbloed et al. 2009).The correspondence between the split time of the Kerey sub-clans and the age estimate of their Y-STR divergence is quite interesting and provides an independent historical argument for the correspondence between the C3* star cluster and Genghis Khan (or at least his direct patrilineal kin). Note that the star cluster's age matches G. K. only using a genealogical mutation rate, and not the widely (mis)used "effective mutation rate. The timeframe is recent enough to render any saturation effects from non-linearity (as described by Busby et al.) relatively unimportant.
The data reported above, taken together with the known arguments in favor of the
possible Genghis Khan‟s descent of Y-chromosome C3* star-cluster (Zerjal et al. 2003), allow us to suggest two hypotheses.
(1) The star-cluster is not directly related to the descendants of Genghis Khan, but rather is associated with the Kerait clan members. Mongol conquest with participation of the Keraits as special Khan‟s military forces allowed them to disseminate the Kerait-specific Y-chromosomes in the vast area inhabited by various peoples.
(2) Genghis Khan by himself belonged to the Keraits. This is supported by the following historical evidence (Man 2004; Khalidullin 2005). The Keraits inhabited the banks of the Onon River, where the camp of Genghis Khan‟s father Yesukhei was located. Yesukhei was declared as a blood brother of the Keraits‟ Khan Toghrul (Wang Khan). Toghrul then declared Genghis Khan his son-in-law. Fraternization of the Genghis Khan family with the Keraits‟ Khan suggests that a real blood relationship, though probably not approved officially, existed between them.
Human Biology: Vol. 84: Iss. 1, Article 4.
The Y-chromosome C3* star-cluster attributed to Genghis Khan's descendants is present at high frequency in the Kerey clan from Kazakhstan
Serikbai Abilev et al.
In order to verify the possibility that the Y-chromosome C3* star-cluster attributed to Genghis Khan and his patrilineal descendants is relatively frequent in the Kereys, who are the dominant clan in Kazakhstan and in Central Asia as a whole, polymorphism of the Y-chromosome was studied in Kazakhs, represented mostly by members of the Kerey clan. The Kereys showed the highest frequency (76.5%) of individuals carrying the Y-chromosome variant known as C3* star-cluster ascribed to the descendants of Genghis Khan. C3* star-cluster haplotypes were found in two sub-clans, Abakh-Kereys and Ashmaily-Kereys, diverged about 20-22 generations ago according to the historical data. Median network of the Kerey star-cluster haplotypes at 17 STR loci displays a bipartite structure, with two subclusters defined by the only difference at DYS448 locus. It is noteworthy that there is a strong correspondence of these subclusters with the Kerey sub-clans affiliation. The data obtained suggest that the Kerey clan appears to be the largest known clan in the world descending from a common Y-chromosome ancestor. Possible ways of Genghis Khan‟s relation to the Kereys are discussed.