...
Post A Reply
my profile
|
directory
login
|
register
|
search
|
faq
|
forum home
»
EgyptSearch Forums
»
Egyptology
»
The genetic structure of the worlds first farmers - Iosif Lazaridis
» Post A Reply
Post A Reply
Login Name:
Password:
Message Icon:
Message:
HTML is not enabled.
UBB Code is enabled.
[QUOTE]Originally posted by Tukuler: [QB] In addition to carrying new information about phylogeny, the polymorphisms here analyzed are informative about the timing of lineage divergence. For each node in the tree, we obtained dating estimates using both the rho method (Forster et al. 1996) and a Bayesian approach implemented in BEAST (Drummond and Rambaut 2007) (fig. 1), using a nucleotide substitution rate of 0.716 Χ 10−9/site/year specific for the MSY regions here analyzed. Dating estimates are reported in supplementary table S6, Supplementary Material online. As the two methods produced highly concordant values (r = 0.997; supplementary fig. S1, Supplementary Material online), hereafter we only refer to the results obtained using BEAST. The TMRCA (time to the most recent common ancestor) for all haplogroup E chromosomes here analyzed is 57.4 ka (95% CI: 50.068.0 ka), older than the estimates of about 37 ka reported by Semino et al. (2004) and Hallast et al. (2015) using an STR- and SNP-based dating, respectively. These inconsistencies in TMRCA estimates are probably due to Y-STR mutation count saturation (Wei, Ayub, Xue, et al. 2013) in the first case (Semino et al. 2004) and to the use of a different SNP mutation rate (1.0 Χ 10−9/mutations/nucleotide/year) in the second case (Hallast et al. 2015). In the subsequent 20 ky, four major dichotomies were observed: 1) The split between E-M33 and E-P2 subhaplogroups, dated at 54.4 ka (95% CI: 47.464.4 ka); 2) the node separating E-V38 and E-M215 branches (47.5 ka; 95% CI: 41.356.8 ka); and 3) two unexpectedly old (45.6 and 38.6 ka; 95% CI: 38.453.7 and 31.445.9 ka, respectively) nodes which separate two common and widespread African haplogroups (E-M2 and E-M35) from two rare eastern African lineages (E-M329 and E-V16), respectively. Another striking aspect of our dating is the previously unappreciated large difference in the age between haplogroup E-M215 (38.6 ka; 95% CI: 31.445.9 ka) and its subhaplogroup E-M35 (25.0 ka; 95% CI: 20.030.0 ka). Within the E-V68 subclade, the M78 mutation arose in a time window between 20.3 ka (95% CI: 16.225.4 ka) and 14.8 ka (95% CI: 11.618.5 ka), namely the TMRCA for E-V68 and E-M78, respectively. The TMRCA of E-V13 chromosomes (8.1 ka; 95% CI: 5.610.8 ka) consistent with a previous hypothesis about a post-Neolithic expansion of this haplogroup in Europe (Cruciani et al. 2004, 2007). Finally, the young TMRCA (3.5 ka; 95% CI: 1.75.9 ka) for the node separating the sequenced (former) E-M35* and E-M293 samples suggests a TMRCA for the M293 variant more recent than previously hypothesized using an STR-based dating (11.4 ka; Henn et al. [2008]). [/QB][/QUOTE]
Instant Graemlins
Instant UBB Code™
What is UBB Code™?
Options
Disable Graemlins in this post.
*** Click here to review this topic. ***
Contact Us
|
EgyptSearch!
(c) 2015 EgyptSearch.com
Powered by UBB.classic™ 6.7.3