A comparison of the human and chimpanzee olfactory receptor gene repertoires
A comparison of the human and chimpanzee olfactory receptor gene repertoires
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DOI：
10.1101/gr.2846405
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发表时间：
2005-02-01
期刊：
影响因子：
7
通讯作者：
Glusman, G
中科院分区：
文献类型：
--
作者：
Gilad, Y;Man, O;Glusman, G
嗅觉受体(OR)基因构成嗅觉的基础，由最大的哺乳动物基因超家族编码，有1000个成员。在人类中，而不是在老鼠或狗中，大多数OR基因已经成为假基因，这表明人类的OR基因在不同于其他哺乳动物的选择压力下进化。为了进一步探索这一点，我们利用最近测序的黑猩猩基因组，将人类的OR基因库与其最接近的现存进化亲戚进行了比较。与以前基于少量OR的报告一致，我们发现人类OR假基因的比例明显高于黑猩猩。此外，我们可以排除这样一种可能性，即自人类和黑猩猩分化以来，人类一直在以恒定的中性速度积累OR伪基因。对这两个谱系的比较发现了两个黑猩猩特有的OR亚家族的扩展和三个人类特有的扩展。这也表明，在人类或黑猩猩的血统中，OR基因的一个子集处于正向选择之下。因此，尽管总体上相对于黑猩猩来说，人类的嗅觉受到了放松的限制，但物种特定的感觉需求似乎塑造了这两个物种功能OR基因谱的进化。
Olfactory receptor (OR) genes constitute the basis of the sense of smell and are encoded by the largest mammalian gene superfamily, with >1000 members. In humans, but not in mice or dogs, the majority of OR genes have become pseudogenes, suggesting that OR genes in humans evolve under different selection pressures than in other mammals. To explore this further, we compare the OR gene repertoire of human with its closest living evolutionary relative, by taking advantage of the recently sequenced genome of the chimpanzee. In agreement with previous reports based on a small number of ORs, we find that humans have a significantly higher proportion of OR pseudogenes than chimpanzees. Moreover, we can reject the possibility that humans have been accumulating OR pseudogenes at a constant neutral rate since the divergence of human and chimpanzee. The comparison of the two repertoires reveals two chimpanzee-specific OR Subfamily expansions and three expansions specific to humans. It also suggests that a subset of OR genes are under positive selection in either the human or the chimpanzee lineage. Thus, although overall there is relaxed constraint on human olfaction relative to chimpanzee, species-specific sensory requirements appear to have shaped the evolution of the functional OR gene repertoires in both species.