Evolution of duplicated growth hormone genes in autotetraploid salmonid fishes
Evolution of duplicated growth hormone genes in autotetraploid salmonid fishes
复制标题
DOI：
10.1139/g04-018
复制
发表时间：
2004-08-01
期刊：
影响因子：
3.1
通讯作者：
Devlin, RH
中科院分区：
文献类型：
--
作者：
McKay, SJ;Trautner, J;Devlin, RH
鲑科鱼类的一个决定性特征是同源四倍体，这是大约2500万-1亿年前基因组加倍事件的结果。最初，复制的基因可能经历了协同进化和四体遗传。同源染色体最终分化，由此导致的平行基因之间重组和基因转换的减少使得二体遗传得以重新建立。在现存的鲑鱼(如鲑鱼、鲑鱼、鲑鱼)中，生长激素(GH)基因通常由两个功能类似物GH1和GH2代表。通过对鲑亚科(白鱼亚科、西斯科亚科)和鲑亚科的鲑鱼生长激素基因的序列分析，研究了这两个重复的生长激素基因的进化历史。在Coregoninae中也发现了两个不同的GH基因同源基因，但它们不属于GH1和GH2类别。Coregonine GH基因之间的平均序列差异比Salmonine GH1和GH2之间的相应差异小两倍以上。对Coregonine GH对虾的系统发育分析没有解决它们与Salmonine对虾的亲缘关系。这些发现表明，在这两个亚家族中，两个生长激素基因的二体遗传是由不同的机制建立的。
A defining character of the piscine family Salmonidae is autotetraploidy resulting from a genome-doubling event some 25-100 million years ago. Initially, duplicated genes may have undergone concerted evolution and tetrasomic inheritance. Homeologous chromosomes eventually diverged and the resulting reduction in recombination and gene conversion between paralogous genes allowed the re-establishment of disomic inheritance. Among extant salmonine fishes (e.g. salmon, trout, char) the growth hormone (GH) gene is generally represented by two functional paralogs, GH1 and GH2. Sequence analyses of salmonid GH genes from species of subfamilies Coregoninae (whitefish, ciscos) and Salmoninae were used to examine the evolutionary history of the duplicated GH genes. Two divergent GH gene paralogs were also identified in Coregoninae, but they were not assignable to the GH1 and GH2 categories. The average sequence divergence between the coregonine GH genes was more than twofold lower than the corresponding divergence between the salmonine GH1 and GH2. Phylogenetic analysis of the coregonine GH paralogs did not resolve their relationship to the salmonine paralogs. These findings suggest that disomic inheritance of two GH genes was established by different mechanisms in these two subfamilies.