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O clades were randomly assigned concentrations

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literaryClarity View Drop Down
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    Posted: 17 Jun 2014 at 06:33
Due to a well known genetic concept called bottlenecking.

First, if you will, please notice coalescent times.


27 27 28 thousand years ago are derivations during the hunter gatherer stage of humankind.  People didn't yet settle down into villages where there would be security afforded to a community of multiple dozens.  Hunter gatherers traveled in bands of one dozen (for comparison purposes).

This means that small bands of O could be harboring any smaller number of individual haplotypes such as couple males with C or D or R and over time their genetic contents get mixed in with the hunter gatherer band of O types.

However because drift often occurred such as accidents, disaster earthquakes, disease etc.  A lot of diversified units like C D J K N O P Q R retaining each instance of their lineage within a traveling band would be highly improbable.  By the time the O types reached the central plains from southern China there would have been reductions.  When these reductions reach a point where there was only one haplotype left they would have likely journeyed separately and wouldn't meet each other until they crossed paths in civilization.

http://www.genetics.org/content/172/4/2431/F2.expansion.html


Notice the maps given and the disparity between north and south.  By the time one reaches north China it wouldn't be surprising to see cases where O types are completely in the zero percent range.  Don't tell me the way easy772 does that all the southern types were murdered off by the northern types when they reached the north and vice versa all the northern types were murdered off by the southern types when they reached the south.


Edited by literaryClarity - 17 Jun 2014 at 10:11
http://hwyst.hangzhou.com.cn/wmyzh/content/2013-10/09/content_4920423.htm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toyomotor Quote  Post ReplyReply Direct Link To This Post Posted: 17 Jun 2014 at 07:18
And here's what the Abstract from the document actually says-
 
Quote Abstract
The human population has increased greatly in size in the last 100,000 years, but the initial stimuli to growth, the times when expansion started, and their variation between different parts of the world are poorly understood. We have investigated male demography in East Asia, applying a Bayesian full-likelihood analysis to data from 988 men representing 27 populations from China, Mongolia, Korea, and Japan typed with 45 binary and 16 STR markers from the Y chromosome. According to our analysis, the northern populations examined all started to expand in number between 34 (18–68) and 22 (12–39) thousand years ago (KYA), before the last glacial maximum at 21–18 KYA, while the southern populations all started to expand between 18 (6–47) and 12 (1–45) KYA, but then grew faster. We suggest that the northern populations expanded earlier because they could exploit the abundant megafauna of the “Mammoth Steppe,” while the southern populations could increase in number only when a warmer and more stable climate led to more plentiful plant resources such as tubers.
 
 
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