能量代谢基因的适应进化及蝙蝠飞行的起源

 

熊荣川 译

 

蝙蝠的飞行提出了飞行在哺乳动物内如何独立进化的有趣问题。飞行是最消耗能量的行为之一。所以我们推断，能量机制的改变一定是飞行在蝙蝠类群内进化的首要因素。线粒体呼吸链提供了运动所必需的95%的三磷酸腺苷ATP。因为呼吸链具有双重遗传特性，其基因同时来自线粒体和核基因组，我们对两者都作了研究以了解飞行在哺乳动物内的进化。在蝙蝠中，23.08%线粒体中编码的氧化磷酸化基因及4.90%核内氧化磷酸化基因检测到正选择，而只有2.25%的在线粒体中发挥作用的非呼吸链核基因或者1.005%的其它一些核基因检测到正选择。考虑到已知的两个蝙蝠基因组数据的局限性，我们重测了四个蝙蝠物种的77个氧化磷酸化基因。经过对重测的基因信息的分析，结果和我们之前的结论一致，即和背景基因对比有相当高比例的基因参与了能量代谢，在蝙蝠的共同祖先上表现出特有的适应进化证据。沿着蝙蝠祖先支系，无论是线粒体中还是核内编码的氧化磷酸化基因，都表现出了适应进化的证据，支持我们之前的假说——在飞行进化起源时，能量相关的基因是自然选择的目标并且朝着适应一定能量需求方向发生巨大改变。

 

关键词：翼手目 遗传机制 线粒体 氧化磷酸化

 

 

Adaptive evolution of energy metabolism genes and the origin of flight in bats

 

Bat flight poses intriguing questions about how flight independently developed in mammals. Flight is among the most energy consuming activities. Thus, we deduced that changes in energy metabolism must be a primary factor in the origin of flight in bats. The respiratory chain of the mitochondrial produces 95% of the adenosine triphosphate (ATP) needed for locomotion. Because the respiratory chain has a dual genetic foundation, with genes encoded by both the mitochondrial and nuclear genomes, we examined both genomes to gain insights into the evolution of flight within mammals. Evidence for positive selection was detected in 23.08% of the mitochondrial-encoded and 4.90% of nuclearencoded oxidative phosphorylation (OXPHOS) genes, but in only 2.25% of the nuclear-encoded nonrespiratory genes that function in mitochondria or 1.005% of other nuclear genes in bats. To address the caveat that the two available bat genomes are of only draft quality, we resequenced 77 OXPHOS genes from four species of bats. The analysis of the resequenced gene data are in agreement with our conclusion that a significantly higher proportion of genes involved in energy metabolism, compared with background genes, show evidence of adaptive evolution specific on the common ancestral bat lineage. Both mitochondrial and nuclearencoded OXPHOS genes display evidence of adaptive evolution along the common ancestral branch of bats, supporting our hypothesis that genes involved in energy metabolism were targets of natural selection and allowed adaptation to the huge change in energy demand that were required during the origin of flight.(Shen et al., 2010)

 

Chiroptera | genetic foundation | mitochondria | OXPHOS

 

参考文献：

Shen Yong-Yi, Liang Lu, Zhu Zhou-Hai, Zhou Wei-Ping, Irwin David M.,Zhang Ya-Ping (2010). "Adaptive evolution of energy metabolism genes and the origin of flight in bats." Proceedings of the National Academy of Sciences.

 

 

 

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