脊椎动物中Emx基因的进化与大脑发育
Evolution of Emx genes and brain development in vertebrates.
作者信息
Patarnello T, Bargelloni L, Boncinelli E, Spada F, Pannese M, Broccoli V
机构信息
Department of Biology, University of Padova, Italy.
出版信息
Proc Biol Sci. 1997 Dec 22;264(1389):1763-6. doi: 10.1098/rspb.1997.0244.
Emx1 and Emx2 genes are known to be involved in mammalian forebrain development. In order to investigate the evolution of the Emx gene family in vertebrates, a phylogenetic analysis was carried out on the Emx genes sequenced in man, mice, frogs, coelacanths and zebrafish. The results demonstrated the existence of two clades (Emx1 and Emx2), each grouping one of the two genes of the investigated taxa. The only exception was the zebrafish Emx1-like gene which turned out to be a sister group to both the Emx1 and Emx2 clusters. Such striking sequence divergence observed for the zebrafish Emx1-like gene could indicate that it is not orthologous to the other Emx1 genes, and therefore, in vertebrates there must be three Emx genes. Alternatively, if the zebrafish emx1 gene is orthologous to the tetrapod one, it must have undergone to strong diversifying selection.
已知Emx1和Emx2基因参与哺乳动物前脑发育。为了研究脊椎动物中Emx基因家族的进化，对人类、小鼠、青蛙、腔棘鱼和斑马鱼中测序的Emx基因进行了系统发育分析。结果表明存在两个进化枝（Emx1和Emx2），每个进化枝将所研究分类群的两个基因之一归为一组。唯一的例外是斑马鱼Emx1样基因，它是Emx1和Emx2基因簇的姐妹群。斑马鱼Emx1样基因观察到的这种显著序列差异可能表明它与其他Emx1基因不是直系同源的，因此，在脊椎动物中一定有三个Emx基因。或者，如果斑马鱼emx1基因与四足动物的emx1基因是直系同源的，那么它一定经历了强烈的多样化选择。
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