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7万年前线粒体单倍群L3返回非洲

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发表于 2018-6-24 23:27 | 显示全部楼层 |阅读模式
本帖最后由 ChinaHistory 于 2018-6-24 23:29 编辑

https://bmcevolbiol.biomedcentral.com/articles/10.1186/s12862-018-1211-4

7万年前线粒体单倍群L3返回非洲

Carriers of mitochondrial DNA macrohaplogroup L3 basal lineages migrated back to Africa from Asia around 70,000 years ago

BMC Evolutionary Biology201818:98

Received: 10 August 2017
Accepted: 5 June 2018
Published: 19 June 2018

Abstract

Background

The main unequivocal conclusion after three decades of phylogeographic mtDNA studies is the African origin of all extant modern humans. In addition, a southern coastal route has been argued for to explain the Eurasian colonization of these African pioneers. Based on the age of macrohaplogroup L3, from which all maternal Eurasian and the majority of African lineages originated, the out-of-Africa event has been dated around 60-70 kya. On the opposite side, we have proposed a northern route through Central Asia across the Levant for that expansion and, consistent with the fossil record, we have dated it around 125 kya. To help bridge differences between the molecular and fossil record ages, in this article we assess the possibility that mtDNA macrohaplogroup L3 matured in Eurasia and returned to Africa as basal L3 lineages around 70 kya.

Results

The coalescence ages of all Eurasian (M,N) and African (L3 ) lineages, both around 71 kya, are not significantly different. The oldest M and N Eurasian clades are found in southeastern Asia instead near of Africa as expected by the southern route hypothesis. The split of the Y-chromosome composite DE haplogroup is very similar to the age of mtDNA L3. An Eurasian origin and back migration to Africa has been proposed for the African Y-chromosome haplogroup E. Inside Africa, frequency distributions of maternal L3 and paternal E lineages are positively correlated. This correlation is not fully explained by geographic or ethnic affinities. This correlation rather seems to be the result of a joint and global replacement of the old autochthonous male and female African lineages by the new Eurasian incomers.

Conclusions

These results are congruent with a model proposing an out-of-Africa migration into Asia, following a northern route, of early anatomically modern humans carrying pre-L3 mtDNA lineages around 125 kya, subsequent diversification of pre-L3 into the basal lineages of L3, a return to Africa of Eurasian fully modern humans around 70 kya carrying the basal L3 lineages and the subsequent diversification of Eurasian-remaining L3 lineages into the M and N lineages in the outside-of-Africa context, and a second Eurasian global expansion by 60 kya, most probably, out of southeast Asia. Climatic conditions and the presence of Neanderthals and other hominins might have played significant roles in these human movements. Moreover, recent studies based on ancient DNA and whole-genome sequencing are also compatible with this hypothesis.



Fig. 1   Geographic origin and dispersion of mtDNA L haplogroups: a Sequential expansion of L haplogroups inside Africa and exit of the L3 precursor to Eurasia. b Return to Africa and expansion to Asia of basal L3 lineages with subsequent differentiation in both continents. The geographic ranges of Neanderthals, Denisovans and Erectus are estimates only

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发表于 2018-6-25 09:23 | 显示全部楼层
本帖最后由 xavierxh 于 2018-6-25 10:37 编辑

1# ChinaHistory
1、早先的mtDNA研究的结论是所有现存的现代人类的非洲起源,沿南部沿海路线(中东、西亚、南亚的南部沿线扩张路线)也被用来解释这些非洲拓荒者(母系线粒体L3),这个早前的结论基于线粒体L3(所有的母系欧亚大陆和大多数非洲血统起源)的诞生年龄,即走出非洲的时间定位于6-7万年前。相反的,我们目前的研究提出了一条线粒体L?(L非洲19.2万年前、L1非洲16.6万年前、L5非洲14.9万年前的后代,L3非洲7.16万年前的祖先)穿越中亚的北路线(起源东南亚——穿过西亚——中东——地中海东部黎凡特——非洲路线进行扩张),这条路线与古人类化石记录一致,我们把它(线粒体L?)定在12.5万年前左右(线粒体L、L1、L5的后代或者姐妹在12.5万年前从非洲到达东南亚又从东南亚经西亚中东回到非洲进化成为L3)。为了帮助弥合分子人类生物学研究和化石记录研究对于人类迁徙进化时间之间的差异,在本文中,我们评估的可能性,线粒体DNA基因组群L3的祖先在欧亚大陆进化诞生,并返回非洲进化成为L3谱系在7万年前左右。
2、所有线粒体欧亚(M,N)和非洲(L3)谱系的同一母系祖先时间在7.1 万年前左右。最古老的M和N欧亚分支发现在东南亚而不是非洲附近,正如南部路线假说所预期的那样。Y染色体复合单倍体群的分裂与线粒体DNA L3的年龄非常相似。在非洲的非洲Y染色体单倍型群E由欧亚大陆起源和向非洲迁徙,母体L3和父系E系的频率分布呈正相关。这种相关性没有完全解释地理或民族亲缘关系。这种相关性似乎是由新欧亚传入者(母系L3、父系E)对旧非洲原地父系(?)和母系非洲(?)替代的结果。
3、这些结果与提出非洲迁徙到亚洲的一个模型相一致,这是一条北方路线,12.5万年前L3的祖先——前L3线粒体DNA谱系到达亚洲,随后前L3线粒体进化为L3的基础谱系从东南亚经欧亚大陆回到非洲。大约7万年前全现代人类L?(母系前L3谱系)在非洲之外的M和N系在欧亚大陆继续进化,第二次欧亚大陆现代人类的祖先的全球扩张最有可能起源于6万年前的东南亚。气候条件因素、尼安德特人、丹尼索瓦人和同时期(12.5万年前——19.2万年前)存在的其他直立人,在进化迁徙路线中扮演了重要角色(和智人混血促进人类进化)。此外,基于古DNA和全基因组测序的最新研究也与这一假说相一致。
发表于 2018-6-25 10:45 | 显示全部楼层
按这个文章:

父系单倍群从非洲向外扩张;母系线粒体从东南亚向欧亚向非洲扩张。最古老的M、N的线粒体年龄与L3年龄相当。

1、如何解释L3在欧亚大陆没有发现上游?尤其在东南亚。

2、有如此强大的线粒体覆盖范围,为何没有覆盖自非洲出来的父系单倍群?而是相反被非洲父系单倍群覆盖?
发表于 2018-6-25 10:46 | 显示全部楼层
这篇BMC Evolutionary Biology(英国《BMC进化生物学》,在SCI影响因子3.4)最新论文和我15年在论坛的一篇猜测相一致。
发表于 2018-6-25 11:03 | 显示全部楼层
本帖最后由 xavierxh 于 2018-6-25 11:19 编辑
按这个文章:

父系单倍群从非洲向外扩张;母系线粒体从东南亚向欧亚向非洲扩张。最古老的M、N的线粒体年龄与L3年龄相当。

1、如何解释L3在欧亚大陆没有发现上游?尤其在东南亚。

2、有如此强大的线粒体覆盖 ...
hxr7353 发表于 2018-6-25 10:45

1、这篇文章没有提及:父系单倍群从非洲向外扩张,母系线粒体从东南亚向欧亚向非洲扩张。   但是我认为文中这句正确:起源于东南亚的前L3母系及相关父系(文中没说)作为新欧亚传入者(母系L3、父系E)对旧非洲原地父系(?)和母系非洲(?)替代。
2、如何解释L3在欧亚大陆没有发现上游?尤其在东南亚。答:猜测L3上游即文中的前L3在欧亚大陆被MN的后代竞争替换了,但是估计欧亚大陆包括东南亚特别是一些偏远岛屿有遗存。我猜测澳洲土著母系肯定有前L3,阿奴伊人的母系中可能也有前L3,南美洲与世隔绝森林极个别土著部落母系中肯定也有前L3。前L3和MN后代的竞争优势差距较大,在容易迁徙到达的欧亚大陆肯定是混血少绝大多数被取代的情况多。
3、有如此强大的线粒体覆盖范围,为何没有覆盖自非洲出来的父系单倍群?而是相反被非洲父系单倍群覆盖?答:看不懂你的问题,人类进化历史上近几十万年来,在不同时期,有进化优势的一波一波的线粒体出非洲,一波一波的线粒体出南亚,一波一波的线粒体出东南亚,一波一波的线粒体出中东,一波一波的线粒体出西亚。彼此竞争混血或者替代,很复杂的。
发表于 2018-6-27 19:00 | 显示全部楼层
本帖最后由 skyyrie 于 2018-6-28 12:26 编辑

不错的文章

There are no native D lineages in India, decreasing the possibility that this subcontinent was the center of the DE partition, which argues against a southern route. It is likely that the divergence of the Y-chromosome D and E haplogroups occurred up to the Himalayas and in or westward of the Tibet which coincides with the hypothetical bifurcation center proposed for the mtDNA L3 macrohaplogroup.


这个文章说 Y DE是在喜马拉雅北坡分开的
并且mt DNA L3也是在这里分开的。
发表于 2018-7-3 01:31 | 显示全部楼层
本帖最后由 Danny 于 2018-7-3 01:33 编辑

2# xavierxh 感觉三是对的时间7万年前
发表于 2018-7-3 14:18 | 显示全部楼层
2# xavierxh 感觉三是对的时间7万年前
Danny 发表于 2018-7-3 01:31

是的,14年接触分子人类学,直觉东亚可能也是重要的进化优势出发地。
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