科研人员发现，东亚人的祖先可能曾与一个与丹尼索瓦人（Denisovans）有关系的古代群体杂交繁殖。丹尼索瓦人是以发现其残骸的西伯利亚丹尼索瓦洞穴而命名的古人类。
丹尼索瓦人（Denisovans）
此前的研究提示，在古人类和现代人类的祖先从非洲出现之后，他们之间有两次独立的杂交繁殖事件：一次事件涉及了尼安德特人，并且产生了今天的非洲人群，而另一次事件涉及了丹尼索瓦人，产生了今天的大洋洲人。
Pontus Skoglund和Mattias Jakobsson通过比较来自全世界1500多位现代人的遗传数据和近来测出的一个尼安德特人和一个丹尼索瓦人的基因组，从而搜寻古人类世系的额外的地理模式。
这组作者发现，和大洋洲人类似，东南亚人拥有较高频率的丹尼索瓦人相关遗传特征，这些特征在其他现代人群（包括欧洲人、美洲人和西亚/中亚人）并不常见。在比较了人类从非洲扩张出去的三个计算机模型之后，这组作者提出，在东南亚的丹尼索瓦人世系可以通过丹尼索瓦人与东亚大陆的现代人祖先的杂交繁殖得到最好的解释。(生物探索)
相关英文论文摘要：
Archaic human ancestry in East Asia
Recent studies of ancient genomes have suggested that gene flow from archaic hominin groups to the ancestors of modern humans occurred on two separate occasions during the modern human expansion out of Africa. At the same time, decreasing levels of human genetic diversity have been found at increasing distance from Africa as a consequence of human expansion out of Africa. We analyzed the signal of archaic ancestry in modern human populations, and we investigated how serial founder models of human expansion affect the signal of archaic ancestry using simulations. For descendants of an archaic admixture event, we show that genetic drift coupled with ascertainment bias for common alleles can cause artificial but largely predictable differences in similarity to archaic genomes. In genotype data from non-Africans, this effect results in a biased genetic similarity to Neandertals with increasing distance from Africa. However, in addition to the previously reported gene flow between Neandertals and non-Africans as well as gene flow between an archaic human population from Siberia (“Denisovans”) and Oceanians, we found a significant affinity between East Asians, particularly Southeast Asians, and the Denisova genome—a pattern that is not expected under a model of solely Neandertal admixture in the ancestry of East Asians. These results suggest admixture between Denisovans or a Denisova-related population and the ancestors of East Asians, and that the history of anatomically modern and archaic humans might be more complex than previously proposed.
英文论文链接：https://www.pnas.org/content/early/2011/10/24/1108181108.abstract
