Acquisition or loss of flying ability is evolutionarily linked with maximum life span (MLS) in mammals and birds. Although ecological factors, such as extrinsic mortality, may lead to either shortened or extended life spans through natural selection, MLS is influenced by complex molecular and metabolic processes, and the genetic changes associated with flying ability that have led to either a longer or shorter MLS are unknown. Here, we examine the parallel evolution of flight in mammals and birds and investigate positively selected genes at branches where either the acquisition (in little brown bats and large flying foxes) or loss (in Adélie penguins, emperor penguins, common ostriches, emus, great spotted kiwis, little spotted kiwis, okarito brown kiwis, greater rheas, lesser rheas, and cassowaries) of flight abilities occurred. Although we found no shared genes under selection among all the branches of interest, 7 genes were found to be positively selected in 2 of the branches. Among the 7 genes, only IGF2BP2 is known to affect both life span and energy expenditure. The positively selected mutations detected in IGF2BP2 likely affected the functionality of the encoded protein. IGF2BP2 , which has been reported to simultaneously prolong life span and increase energy expenditure, could be responsible for the evolution of shortened MLS associated with the loss of flying ability.

中文翻译：

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寿命短的遗传因素与飞行能力丧失的演变有关。

飞行能力的获得或丧失与哺乳动物和鸟类的最大寿命（MLS）进化相关。尽管诸如自然死亡等生态因素可能通过自然选择导致寿命缩短或延长，但MLS受复杂的分子和代谢过程影响，而与飞行能力相关的遗传变化导致MLS变长或变短未知。在这里，我们研究了哺乳动物和鸟类中飞行的平行进化，并研究了分支的阳性选择基因，这些分支要么是采集（在小棕蝙蝠和大型果蝠中），要么是丢失（在阿德利企鹅，帝企鹅，普通鸵鸟，em，大）中。出现了斑点奇异果，斑点极少奇异果，奥卡里托棕色奇异果，较大的瑞亚，较小的瑞亚和食火鸡。尽管我们没有发现所有感兴趣的分支都在选择共享基因，但是发现有7个基因在其中两个分支中被阳性选择。在这7个基因中，只有众所周知，IGF2BP2会影响寿命和能量消耗。在IGF2BP2中检测到的阳性选择突变可能会影响编码蛋白的功能。据报道，IGF2BP2可同时延长寿命和增加能量消耗，这可能是导致飞行能力丧失与缩短的MLS进化的原因。