Why are olfactory systems of different animals so similar?
Why are olfactory systems of different animals so similar?
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DOI：
10.1159/000063564
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发表时间：
2002-01-01
影响因子：
1.7
通讯作者：
Eisthen, HL
中科院分区：
文献类型：
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作者：
Eisthen, HL
随着我们对嗅觉神经生物学的了解越来越多，越来越清楚的是，不同门动物的嗅觉系统具有许多共同的显著特征。为什么？为什么？这些特征是否为神经系统处理嗅觉信息的方式提供了线索？如果这些共性是趋同的适应性，具有相似的功能，那么情况可能就是这样，但是相似的特征可以出于其他原因存在于不同的动物中。例如，相似的特征可能是由于从共同祖先（同源性）继承而来，可能代表对相似约束的反应，或者可能是表面的或反映研究系统的研究人员使用的策略。在本文中，我研究了四个例子的嗅觉系统的功能在不同的门的成员：气味结合蛋白的存在下，在液体覆盖的嗅觉受体神经元;使用G蛋白偶联受体作为气味受体;使用一个两步通路的气味信号的转导;和存在的第一个中央目标的嗅觉受体细胞的轴突中的肾小球neuropil。我分析数据从线虫，节肢动物，软体动物和脊椎动物调查这些功能的系统发育分布，并试图解释这些功能在不同的动物的存在。系统发育分析表明，这些特征在各门之间并不同源。尽管这些特征通常被解释为趋同适应，但我发现其他解释很难被忽视。在许多情况下，似乎嗅觉系统的功能是跨门相似的可能反映了类似的约束和适应类似的任务。版权所有（C）2002 S. Karger AG，巴塞尔。
As we learn more about the neurobiology of olfaction, it is becoming increasingly clear that olfactory systems of animals in disparate phyla possess many striking features in common. Why? Do these features provide clues about the ways the nervous system processes olfactory information? This might be the case if these commonalities are convergent adaptations that serve similar functions, but similar features can be present in disparate animals for other reasons. For example, similar features may be present because of inheritance from a common ancestor (homology), may represent responses to similar constraints, or may be superficial or reflect strategies used by researchers studying the system. In this paper, I examine four examples of features of olfactory systems in members of different phyla: the presence of odorant binding proteins in the fluid overlying olfactory receptor neurons; the use of G protein-coupled receptors as odorant receptors; the use of a two-step pathway in the transduction of odorant signals; and the presence of glomerular neuropils in the first central target of the axons of olfactory receptor cells. I analyze data from nematodes, arthropods, molluscs, and vertebrates to investigate the phylogenetic distribution of these features, and to try to explain the presence of these features in disparate animals. Phylogenetic analyses indicate that these features are not homologous across phyla. Although these features are often interpreted as convergent adaptations, I find that alternative explanations are difficult to dismiss. In many cases, it seems that olfactory system features that are similar across phyla may reflect both responses to similar constraints and adaptations for similar tasks. Copyright (C) 2002 S. Karger AG, Basel.