Comparative genomics provides new insights into the remarkable adaptations of the African wild dog (Lycaon pictus)
Comparative genomics provides new insights into the remarkable adaptations of the African wild dog (Lycaon pictus)
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DOI：
10.1038/s41598-019-44772-5
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发表时间：
2019-06-06
影响因子：
4.6
通讯作者：
Wayne, Robert K.
中科院分区：
文献类型：
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作者：
Chavez, Daniel E.;Gronau, Ilan;Wayne, Robert K.
在犬科动物中，非洲野狗(Lycaon Pictus)在体态适应(专门用于奔跑)方面是最专业的，它们的前脚只有四个脚趾。此外，这个物种是少数被认为是专性食肉动物的犬类之一，拥有强壮的牙齿来捕获大型猎物，并显示出哺乳动物中最多变的毛色之一。在这里，我们使用比较基因组分析来研究非洲野狗的进化历史和遗传基础，这些进化和遗传基础与犬种的花冠、超树冠和毛色变化有关。全基因组扫描显示了独特的氨基酸缺失，这表明发育中的第一个手指通过扩大细胞凋亡而导致进化中的手指丢失。非洲野狗特有的正选择信号也揭示了一种可能的磨牙尖修饰机制，即与牙齿空间图案形成所需的声波刺猬(SHH)信号通路相关的基因以及与色素沉着相关的三个基因的变化。分歧时间分析表明，我们发现的一系列基因组变化类似于1.7 Mya，与大型有蹄类的多样化相吻合。我们的结果表明，比较基因组学是识别犬科进化变化的遗传基础的有力工具。
Within the Canidae, the African wild dog (Lycaon pictus) is the most specialized with regards to cursorial adaptations (specialized for running), having only four digits on their forefeet. In addition, this species is one of the few canids considered to be an obligate meat-eater, possessing a robust dentition for taking down large prey, and displays one of the most variable coat colorations amongst mammals. Here, we used comparative genomic analysis to investigate the evolutionary history and genetic basis for adaptations associated with cursoriality, hypercanivory, and coat color variation in African wild dogs. Genome-wide scans revealed unique amino acid deletions that suggest a mode of evolutionary digit loss through expanded apoptosis in the developing first digit. African wild dog-specific signals of positive selection also uncovered a putative mechanism of molar cusp modification through changes in genes associated with the sonic hedgehog (SHH) signaling pathway, required for spatial patterning of teeth, and three genes associated with pigmentation. Divergence time analyses suggest the suite of genomic changes we identified evolved similar to 1.7 Mya, coinciding with the diversification of large-bodied ungulates. Our results show that comparative genomics is a powerful tool for identifying the genetic basis of evolutionary changes in Canidae.