Human Genetic Data Reveal Contrasting Demographic Patterns between Sedentary and Nomadic Populations That Predate the Emergence of Farming
Human Genetic Data Reveal Contrasting Demographic Patterns between Sedentary and Nomadic Populations That Predate the Emergence of Farming
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DOI：
10.1093/molbev/mst156
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发表时间：
2013-12-01
影响因子：
10.7
通讯作者：
Austerlitz, Frederic
中科院分区：
文献类型：
--
作者：
Aime, Carla;Laval, Guillaume;Austerlitz, Frederic
已知人口变化会在遗传多态性上留下足迹。随着大型多态性数据集的可用性增加，基于聚结的方法可以从当今的遗传多样性模式推断过去的人口统计学。在这里，我们分析了细胞核（20个非编码区）和线粒体（HVS-I）重测序数据，以推断66个非洲和欧亚人口的人口统计学历史，这些人口呈现出截然不同的生活方式（游牧狩猎采集者，游牧民和定居农民）。这使我们能够调查生活方式和人口统计之间的关系，并解决有关人口扩张和新石器时代过渡的时间顺序的长期争论。在非洲，我们推断农民的扩张事件，但狩猎采集者的人口规模不变或收缩事件。在欧亚大陆，除了中亚和韩国，我们推断农民的扩张率高于牧民的HVS-I数据。虽然隔离和混合过程可能会影响我们的人口推断，这些过程本身似乎不太可能解释不同生活方式的人群中推断出的对比人口历史。由此推断，牧民和狩猎采集者的小规模扩张率或恒定的人口规模可能是与游牧有关的制约因素造成的。然而，常染色体数据显示，收缩事件的两个久坐人群在欧亚大陆，这可能是由创始人效应。最后，推断的扩张可能早于农业和畜牧业的出现。这表明，人类人口可能在旧石器时代开始扩张，而旧石器时代某些人口的强劲扩张可能最终有利于他们在新石器时代转向农业。
Demographic changes are known to leave footprints on genetic polymorphism. Together with the increased availability of large polymorphism data sets, coalescent-based methods allow inferring the past demography of populations from their present-day patterns of genetic diversity. Here, we analyzed both nuclear (20 noncoding regions) and mitochondrial (HVS-I) resequencing data to infer the demographic history of 66 African and Eurasian human populations presenting contrasting lifestyles (nomadic hunter-gatherers, nomadic herders, and sedentary farmers). This allowed us to investigate the relationship between lifestyle and demography and to address the long-standing debate about the chronology of demographic expansions and the Neolithic transition. In Africa, we inferred expansion events for farmers, but constant population sizes or contraction events for hunter-gatherers. In Eurasia, we inferred higher expansion rates for farmers than herders with HVS-I data, except in Central Asia and Korea. Although isolation and admixture processes could have impacted our demographic inferences, these processes alone seem unlikely to explain the contrasted demographic histories inferred in populations with different lifestyles. The small expansion rates or constant population sizes inferred for herders and hunter-gatherers may thus result from constraints linked to nomadism. However, autosomal data revealed contraction events for two sedentary populations in Eurasia, which may be caused by founder effects. Finally, the inferred expansions likely predated the emergence of agriculture and herding. This suggests that human populations could have started to expand in Paleolithic times, and that strong Paleolithic expansions in some populations may have ultimately favored their shift toward agriculture during the Neolithic.