Relationships between gene diversity and organismal evolution

动物通过基因复制和结构域洗牌，进化出参与细胞间交流和发育控制的各种基因家族。每个家族由几个结构和功能不同的亚型或亚家族组成，这些亚型或亚家族在对偶氮菌和真核偶氮菌分化之前，通过基因复制和结构域洗牌而分化。自从与原口动物分离以来，脊椎动物在鱼-四足动物分裂之前的早期进化中，通过进一步的基因复制扩大了同一亚家族成员(亚型)的多样性。为了更好地了解异构体复制的日期，我们对文昌鱼、灯盏花、hagfsh和七鳃鳗的蛋白酪氨酸激酶家族的四个不同亚型、蛋白酪氨酸磷酸酶家族的五个亚型以及其他三个基因家族的基因进行了分离和测序。根据最大似然法建立的各亚科的系统发育树，结合基于最大似然法的Bootstrap分析，我们发现在脊椎动物的早期进化过程中，由于基因复制和可能的染色体复制，在脊椎动物的环口和颌口分化之前或附近经常发生异构体复制。

Animals evolved a variety of gene families involved in cell-cell communication and developmental control by gene duplication and domain shuffling. Each family comprises several subtypes or subfamilies with distinct structures and functions which diverged by gene duplications and domain shuffling before the divergence of parazoans and eumetazoans. Since the separation from protostomes, vertebrates expanded the multiplicity of members (isoforms) in the same subfamily by further gene duplications in their early evolution before the fish-tetrapod split. To know the dates of isoform duplications more closely, we have conducted isolation and sequencing of genes belonging to four different subtypes of the protein tyrosine kinase family, five subtypes of protein tyrosine phosphatase family, and other three gene families from Branchiostoma belcheri, an amphioxus, Eptatretus burgeri, a hagfsh and Lampetra reissneri, a lamprey. From a phylogenetic tree of each subfamily inferred from a maximum likelihood (ML) method, together with a bootstrap analysis based on the ML method, we have shown that the isoform duplications frequently occurred in the early evolution of vertebrates around or just before the divergence of cyclostomes and gnathostomes by gene dupli-cations and possibly chromosomal duplications.