从解剖上来讲,现代人在距今20万年前之后的某个时间点上还在非洲,在此之后相当长时间才达到欧亚大陆。与此同时,包括“尼安德特人”(穴居人)在内的古“人族”至少在23万年前就已在欧亚大陆了,只是在距今约3万年前才从化石记录中消失。现在,来自南西伯利亚Denisova Cave中的一个女性古“人族”个体的基因组已根据从一个手指骨中提取的DNA被测序。这个“Denisovan”个体所属的群体与“尼安德特人”有一个共同的起源,而且尽管它并不涉及假设中的从“尼安德特人”向欧亚人的基因流动,但它对今天美拉尼西亚人的基因组的贡献达4-6%。另外,一颗牙齿的线粒体基因组与手指骨的线粒体基因组非常像,这颗牙齿的形态表明,这些“人族”个体在演化上与“尼安德特人”和现代人都是截然不同的。(生物谷Bioon.com)
生物谷推荐原文出处:
Nature doi:10.1038/nature09710
Genetic history of an archaic hominin group from Denisova Cave in Siberia
David Reich,Richard E. Green,Martin Kircher,Johannes Krause,Nick Patterson,Eric Y. Durand,Bence Viola,Adrian W. Briggs,Udo Stenzel,Philip L. F. Johnson,Tomislav Maricic,Jeffrey M. Good,Tomas Marques-Bonet,Can Alkan,Qiaomei Fu,Swapan Mallick,Heng Li,Matthias Meyer,Evan E. Eichler,Mark Stoneking,Michael Richards,Sahra Talamo,Michael V. Shunkov,Anatoli P. Derevianko,Jean-Jacques Hublin,et al.
Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4–6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population ‘Denisovans’ and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans.