Copy number changes in co-expressed odorant receptor genes enable selection for sensory differences in drosophilid species
Copy number changes in co-expressed odorant receptor genes enable selection for sensory differences in drosophilid species
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DOI：
10.1038/s41559-022-01830-y
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发表时间：
2022-07-21
影响因子：
16.8
通讯作者：
Arguello, J. Roman
中科院分区：
文献类型：
--
作者：
Auer, Thomas O.;Alvarez-Ocana, Raquel;Arguello, J. Roman
通过研究果蝇和近缘物种的气味受体亚家族Or67a，作者发现，对共表达受体的独立选择有助于嗅觉信息的物种特异性外周编码。尽管有许多化学受体基因家族扩张和收缩的例子，但这些与它们表达的感觉神经元群体的修饰之间的关系仍不清楚。果蝇的气味受体（Or）家族是解决这个问题的理想选择，因为大多数Or在不同的嗅觉感觉神经元（OSN）类型中表达。因此，Or拷贝数的物种间变化可能表明OSN种群数量的增加或减少。在这里，我们研究了Or67a亚家族，其在D. melanogaster及其近亲：D. simulans，拟谷盗D. sechellia和D.毛里求斯。这些物种的共同祖先有三个Or67a旁系同源物，已经适应性地分化。随着物种形成，两个Or67a旁系同源物在D. melanogaster和D. sechellia，与正在进行的积极选择塑造完整的基因。出乎意料的是，在D. simulans在单个神经元群中共表达，该神经元群投射到与D.黑腹菌因此，虽然感觉通路神经解剖学是保守的，独立的选择共表达受体的物种特异性外周编码。这项工作揭示了一种在很大程度上被嗅觉进化所忽视的适应性变化，提高了类似过程影响其他昆虫Or共表达的可能性。
Studying the odorant receptor subfamily Or67a in Drosophila melanogaster and closely related species, the authors show that independent selection on co-expressed receptors has contributed to species-specific peripheral coding of olfactory information.Despite numerous examples of chemoreceptor gene family expansions and contractions, how these relate to modifications in the sensory neuron populations in which they are expressed remains unclear. Drosophila melanogaster's odorant receptor (Or) family is ideal for addressing this question because most Ors are expressed in distinct olfactory sensory neuron (OSN) types. Between-species changes in Or copy number may therefore indicate increases or reductions in the number of OSN populations. Here we investigated the Or67a subfamily, which exhibits copy number variation in D. melanogaster and its closest relatives: D. simulans, D. sechellia and D. mauritiana. These species' common ancestor had three Or67a paralogues that had already diverged adaptively. Following speciation, two Or67a paralogues were lost independently in D. melanogaster and D. sechellia, with ongoing positive selection shaping the intact genes. Unexpectedly, the functionally diverged Or67a paralogues in D. simulans are co-expressed in a single neuron population, which projects to a glomerulus homologous to that innervated by Or67a neurons in D. melanogaster. Thus, while sensory pathway neuroanatomy is conserved, independent selection on co-expressed receptors has contributed to species-specific peripheral coding. This work reveals a type of adaptive change largely overlooked for olfactory evolution, raising the possibility that similar processes influence other cases of insect Or co-expression.