Faculty of Science and Technology, University of Faroe Islands, FO-100 Tórshavn, Faroe Islands.
Int J Mol Sci. 2021 Feb 4;22(4):1584. doi: 10.3390/ijms22041584.
It was previously shown that the connexin gene family had relatively similar subfamily structures in several vertebrate groups. Still, many details were left unclear. There are essentially no data between tunicates, which have connexins that cannot be divided into the classic subfamilies, and teleosts, where the subfamilies are easily recognized. There are also relatively few data for the groups that diverged between the teleosts and mammals. As many of the previously analyzed genomes have been improved, and many more genomes are available, we reanalyzed the connexin gene family and included species from all major vertebrate groups. The major results can be summarized as follows: (i) The same connexin subfamily structures are found in all Gnathostomata (jawed vertebrates), with some variations due to genome duplications, gene duplications and gene losses. (ii) In contrast to previous findings, birds do not have a lower number of connexins than other tetrapods. (iii) The cyclostomes (lampreys and hagfishes) possess genes in the alpha, beta, gamma and delta subfamilies, but only some of the genes show a phylogenetic affinity to specific genes in jawed vertebrates. Thus, two major evolutionary transformations have occurred in this gene family, from tunicates to cyclostomes and from cyclostomes to jawed vertebrates.
先前的研究表明，连接蛋白基因家族在几个脊椎动物群体中具有相对相似的亚家族结构。然而，仍有许多细节尚不清楚。在被囊动物（具有无法分为经典亚家族的连接蛋白）和硬骨鱼之间，基本上没有数据；而在硬骨鱼中，亚家族很容易识别。在硬骨鱼和哺乳动物分化的群体中，也相对较少的数据。随着许多先前分析的基因组得到了改进，并且有更多的基因组可用，我们重新分析了连接蛋白基因家族，并纳入了来自所有主要脊椎动物群体的物种。主要结果可以总结如下：（i）所有有颌类动物（有颌脊椎动物）都具有相同的连接蛋白亚家族结构，由于基因组加倍、基因加倍和基因丢失，存在一些变化。（ii）与先前的发现相反，鸟类的连接蛋白数量并不比其他四足动物少。（iii）圆口类（七鳃鳗和盲鳗）具有 alpha、beta、gamma 和 delta 亚家族的基因，但只有一些基因与有颌脊椎动物的特定基因具有系统发育亲和力。因此，这个基因家族发生了两次主要的进化转变，从被囊动物到圆口类，再从圆口类到有颌脊椎动物。
