Department of Anthropology, University of Utah, 270 S. 1400 E., Rm. 102, Salt Lake City, UT 84112, USA.
Curr Biol. 2010 Feb 23;20(4):R202-7. doi: 10.1016/j.cub.2009.11.051.
The Americas, the last continents to be entered by modern humans, were colonized during the late Pleistocene via a land bridge across what is now the Bering strait. However, the timing and nature of the initial colonization events remain contentious. The Asian origin of the earliest Americans has been amply established by numerous classical marker studies of the mid-twentieth century. More recently, mtDNA sequences, Y-chromosome and autosomal marker studies have provided a higher level of resolution in confirming the Asian origin of indigenous Americans and provided more precise time estimates for the emergence of Native Americans. But these data raise many additional questions regarding source populations, number and size of colonizing groups and the points of entry to the Americas. Rapidly accumulating molecular data from populations throughout the Americas, increased use of demographic models to test alternative colonization scenarios, and evaluation of the concordance of archaeological, paleoenvironmental and genetic data provide optimism for a fuller understanding of the initial colonization of the Americas.
美洲是现代人最后进入的大陆，在更新世晚期，通过现在的白令海峡的陆桥进行了殖民。然而，最初的殖民事件的时间和性质仍然存在争议。二十世纪中叶的大量经典标记研究充分证明了最早的美洲人是从亚洲起源的。最近，mtDNA 序列、Y 染色体和常染色体标记研究为确认美洲原住民的亚洲起源提供了更高的分辨率，并为美洲原住民的出现提供了更精确的时间估计。但这些数据提出了许多其他问题，涉及到源种群、殖民群体的数量和规模，以及进入美洲的地点。来自美洲各地的人群的分子数据的快速积累，以及对替代殖民情景的人口统计学模型的更多使用，以及对考古学、古环境和遗传数据的一致性的评估，为更全面地了解美洲的最初殖民提供了乐观的前景。
