Department of Zoology, Stockholm University, S-106 91 Stockholm, Sweden.
Mol Ecol. 2012 Jul;21(14):3391-402. doi: 10.1111/j.1365-294X.2012.05525.x. Epub 2012 Mar 23.
The last glaciation was a dynamic period with strong impact on the demography of many species and populations. In recent years, mitochondrial DNA sequences retrieved from radiocarbon-dated remains have provided novel insights into the history of Late Pleistocene populations. However, genotyping of loci from the nuclear genome may provide enhanced resolution of population-level changes. Here, we use four autosomal microsatellite DNA markers to investigate the demographic history of woolly mammoths (Mammuthus primigenius) in north-eastern Siberia from before 60 000 years ago up until the species' final disappearance c.4000 years ago. We identified two genetic groups, implying a marked temporal genetic differentiation between samples with radiocarbon ages older than 12 thousand radiocarbon years before present (ka) and those younger than 9ka. Simulation-based analysis indicates that this dramatic change in genetic composition, which included a decrease in individual heterozygosity of approximately 30%, was due to a multifold reduction in effective population size. A corresponding reduction in genetic variation was also detected in the mitochondrial DNA, where about 65% of the diversity was lost. We observed no further loss in genetic variation during the Holocene, which suggests a rapid final extinction event.
末次冰期是一个充满活力的时期，对许多物种和种群的人口结构产生了强烈影响。近年来，从放射性碳定年的遗骸中提取的线粒体 DNA 序列为了解更新世晚期人口的历史提供了新的视角。然而，核基因组中基因座的基因分型可能会提高对种群水平变化的分辨率。在这里，我们使用四个常染色体微卫星 DNA 标记来研究东北西伯利亚地区的猛犸象（Mammuthus primigenius）的人口历史，时间范围从 6 万年前到大约 4000 年前该物种的最终灭绝。我们确定了两个遗传群体，这表明在放射性碳年龄大于 12 千年前（ka）和小于 9ka 的样本之间存在明显的时间遗传分化。基于模拟的分析表明，这种遗传组成的剧烈变化，包括个体杂合性降低约 30%，是由于有效种群数量的多倍减少所致。在线粒体 DNA 中也检测到了相应的遗传变异减少，其中约 65%的多样性丧失。在全新世期间，我们没有观察到遗传变异的进一步丧失，这表明存在快速的最终灭绝事件。
