低分子量热激蛋白的进化研究

不同物种的低分子量热激蛋白 (sHSP)具有高度保守性 ,sHSP基因的保守性可以为生物进化提供一定的科学依据。对 6 2个低分子量热激蛋白基因 (shsps)与α晶体蛋白进行系统进化分析 ,在系统演化上形成两大分支 ,表明存在共同祖先。而α 晶体蛋白分支又由α 晶体蛋白A与α 晶体蛋白B两个分支构成 ,它们的演化顺序分别为鱼类 (AmalphaA ,OlalphaA) ,两栖类 (XlatphaA ,RcalphaA) ,然后是哺乳类动物与鸟类并行演化 ,与经典的形态系统分类基本一致。但进化树显示两栖类的hsp30 ,血吸虫的卵抗原smp4 0 ,人类hshsp2 5与Bmhsp2 1 4在演化地位中具有独特的作用 ,推测它们在人类与家蚕等物种的演化分析中具有重要地位。同时进化的多样性表明昆虫、鱼、鸟及哺乳动物的shsps以直源进化关系为主。

Phylogenesis and Evolution of the Small Heat-Shock Proteins

Small heat shock proteins are widely distributed in all kinds of organisms,and their family presents extremely conservative sequences.Furthermore its conservation can provide some scientific evidence for species evolution.Hence,we used 62 shsps and α crystallin sequences to detect their evolution relation.They were divided into two groups in the phylogenetic tree,and demonstrated that there was common ancestor in this family.Whatmore,α crystallin group consists of αA and αB,and the evolutionary order of α crystallin are:fish( Amalpha A, Olalpha A),amphibian( Xlapha A, Rcalpha A),mammals and birds.This is in accordance with the classification of traditional morphologic system.However,the hsp 30 of Xlapha A,egg antigen smp 40, hshsp 25 of the human being and Bmhsp 21.4 have specific functions in the evolution.So we infer that they play an important role in the evolution of the human being and silkworm( Bombyx mori ).Meantime,the diversity of shsps illustrated that most of shsps of insect,fish,bird and mammal are orthologous genes.