Genetics of the passenger pigeon The now-extinct passenger pigeon used to be one of the most numerous vertebrates on Earth. Murray et al. examined the genomes of four passenger pigeon samples from different locales within its range. They describe the interplay between passenger pigeon population size, genome structure and recombination, and natural selection. They conclude that a reduction in genetic diversity provided few avenues for the bird to respond to human pressures, which ultimately drove it to extinction. Science, this issue p. 951 The passenger pigeon’s genome exhibits the hallmark of natural selection dominating genome-wide evolution. The extinct passenger pigeon was once the most abundant bird in North America, and possibly the world. Although theory predicts that large populations will be more genetically diverse, passenger pigeon genetic diversity was surprisingly low. To investigate this disconnect, we analyzed 41 mitochondrial and 4 nuclear genomes from passenger pigeons and 2 genomes from band-tailed pigeons, which are passenger pigeons’ closest living relatives. Passenger pigeons’ large population size appears to have allowed for faster adaptive evolution and removal of harmful mutations, driving a huge loss in their neutral genetic diversity. These results demonstrate the effect that selection can have on a vertebrate genome and contradict results that suggested that population instability contributed to this species’s surprisingly rapid extinction.

中文翻译：

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自然选择塑造了旅鸽基因组多样性的兴衰

旅鸽的遗传学 现在已经灭绝的旅鸽曾经是地球上数量最多的脊椎动物之一。默里等人。检查了来自其范围内不同地区的四个旅鸽样本的基因组。他们描述了旅鸽种群大小、基因组结构和重组以及自然选择之间的相互作用。他们得出结论，遗传多样性的减少为鸟类应对人类压力提供了很少的途径，最终导致其灭绝。科学，这个问题 p。951 旅鸽的基因组表现出主导全基因组进化的自然选择特征。灭绝的旅鸽曾经是北美乃至全世界数量最多的鸟类。尽管理论预测大种群的遗传多样性会更高，旅鸽遗传多样性出人意料地低。为了研究这种脱节，我们分析了来自旅鸽的 41 个线粒体基因组和 4 个核基因组，以及来自旅鸽的近亲的带尾鸽的 2 个基因组。旅鸽庞大的种群规模似乎允许更快的适应性进化和消除有害突变，从而导致其中性遗传多样性的巨大损失。这些结果证明了选择可能对脊椎动物基因组产生的影响，并且与表明种群不稳定导致该物种出人意料地迅速灭绝的结果相矛盾。它们是旅鸽的近亲。旅鸽庞大的种群规模似乎允许更快的适应性进化和消除有害突变，从而导致其中性遗传多样性的巨大损失。这些结果证明了选择可能对脊椎动物基因组产生的影响，并且与表明种群不稳定导致该物种出人意料地迅速灭绝的结果相矛盾。它们是旅鸽的近亲。旅鸽庞大的种群规模似乎允许更快的适应性进化和消除有害突变，从而导致其中性遗传多样性的巨大损失。这些结果证明了选择可能对脊椎动物基因组产生的影响，并且与表明种群不稳定导致该物种出人意料地迅速灭绝的结果相矛盾。