Extreme variability among mammalian V1R gene families
Extreme variability among mammalian V1R gene families
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DOI：
10.1101/gr.098913.109
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发表时间：
2010-01-01
期刊：
影响因子：
7
通讯作者：
Trask, Barbara J.
中科院分区：
文献类型：
--
作者：
Young, Janet M.;Massa, Hillary F.;Trask, Barbara J.
我们报告了37个哺乳动物基因组的V1R基因家族的进化分析。V1Rs包括犁鼻器中表达的三个化学感受器家族之一，并有助于信息素检测。我们首先证明，跟踪存档数据可以有效地用于确定V1R家族的大小，并获得大多数V1R家族成员的序列。V1R序列的分析，从跟踪数据和基因组组装表明，物种特异性扩增以前观察到的只有8个物种普遍存在于整个哺乳动物的进化，导致“半私人”V1R剧目为大多数哺乳动物。在小鼠和鸭嘴兽中发现了最大的家族，它们的V1R库先前已经发表，其次是鼠狐猴和兔（分别类似于215和类似于160个完整的V1R）。相比之下，两个蝙蝠物种和海豚没有功能V1Rs，只有假基因，并遭受犁鼻信号转导基因Trpc2失活突变。我们发现，灵长类V1R下降发生在获得三色视觉之前，在进化过程中比以前认为的要早。我们还表明，这是极不可能的，狗V1R剧目的下降发生在人类在驯化过程中施加的选择性压力。每个物种的功能库大小大致与犁鼻器的大小和质量的解剖观察，但是，没有一个单一的生态相关解释了这个基因家族在不同的哺乳动物基因组中的不同命运。V1 Rs提供了迄今为止观察到的最极端的例子之一，即某些基因组中的大规模基因复制，而其他物种中的所有功能基因都丢失了。
We report an evolutionary analysis of the V1R gene family across 37 mammalian genomes. V1Rs comprise one of three chemosensory receptor families expressed in the vomeronasal organ, and contribute to pheromone detection. We first demonstrate that Trace Archive data can be used effectively to determine V1R family sizes and to obtain sequences of most V1R family members. Analyses of V1R sequences from trace data and genome assemblies show that species-specific expansions previously observed in only eight species were prevalent throughout mammalian evolution, resulting in "semiprivate" V1R repertoires for most mammals. The largest families are found in mouse and platypus, whose V1R repertoires have been published previously, followed by mouse lemur and rabbit (similar to 215 and similar to 160 intact V1Rs, respectively). In contrast, two bat species and dolphin possess no functional V1Rs, only pseudogenes, and suffered inactivating mutations in the vomeronasal signal transduction gene Trpc2. We show that primate V1R decline happened prior to acquisition of trichromatic vision, earlier during evolution than was previously thought. We also show that it is extremely unlikely that decline of the dog V1R repertoire occurred in response to selective pressures imposed by humans during domestication. Functional repertoire sizes in each species correlate roughly with anatomical observations of vomeronasal organ size and quality; however, no single ecological correlate explains the very diverse fates of this gene family in different mammalian genomes. V1Rs provide one of the most extreme examples observed to date of massive gene duplication in some genomes, with loss of all functional genes in other species.