Yeo Gare Hoon, Cheah Felicia S H, Winkler Christoph, Jabs Ethylin Wang, Venkatesh Byrappa, Chong Samuel S
Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
Dev Genes Evol. 2009 Jun;219(6):289-300. doi: 10.1007/s00427-009-0290-z. Epub 2009 Jun 30.
Four members of the twist gene family (twist1a, 1b, 2, and 3) are found in the zebrafish, and they are thought to have arisen through three rounds of gene duplication, two of which occurred prior to the tetrapod-fish split. Phylogenetic analysis groups most of the vertebrate Twist1 peptides into clade I, except for the Twist1b proteins of the acanthopterygian fish (medaka, pufferfish, stickleback), which clustered within clade III. Paralogies and orthologies among the zebrafish, medaka, and human twist genes were determined using comparative synteny analysis of the chromosomal regions flanking these genes. Comparative nucleotide substitution analyses also revealed a faster rate of nucleotide mutation/substitution in the acanthopterygian twist1b compared to the zebrafish twist1b, thus accounting for their anomalous phylogenetic clustering. We also observed minimal expression overlap among the four twist genes, suggesting that despite their significant peptide similarity, their regulatory controls have diverged considerably, with minimal functional redundancy between them.
在斑马鱼中发现了twist基因家族的四个成员（twist1a、1b、2和3），它们被认为是通过三轮基因复制产生的，其中两轮发生在四足动物与鱼类分化之前。系统发育分析将大多数脊椎动物的Twist1肽归类为进化枝I，但棘鳍鱼类（青鳉、河豚、棘鱼）的Twist1b蛋白除外，它们聚集在进化枝III中。通过对这些基因侧翼染色体区域的比较同线性分析，确定了斑马鱼、青鳉和人类twist基因之间的旁系同源和直系同源关系。比较核苷酸替代分析还显示，与斑马鱼twist1b相比，棘鳍鱼类twist1b的核苷酸突变/替代率更快，这就解释了它们异常的系统发育聚类。我们还观察到四个twist基因之间的表达重叠最小，这表明尽管它们的肽具有显著相似性，但它们的调控控制已经有了很大差异，它们之间的功能冗余最小。
