节肢动物头区起源和演化机制分析  

THE POSSIBLE GENETIC BASES FOR THE ORIGIN AND EVOLUTION OF ARTHROPOD HEAD

作　　者：王修强[1,2] 陈均远[2] 杨永华[1] 

机构地区：[1]南京大学生命科学学院,医药生物技术国家重点实验室,南京210093 [2]中国科学院南京地质古生物研究所,现代古生物学和地层学国家重点实验室,南京210008

出　　处：《古生物学报》2005年第3期446-453,共8页Acta Palaeontologica Sinica

基　　金：中国博士后科学基金(No.2004035212);江苏省博士后科研资助计划;中国科学院南京地质古生物研究所现代古生物学和地层学国家重点实验室(No.053105)和国家重点基础研究发展规划项目(No.G2000077700)资助课题。

摘　　要：帽天山页岩动物群研究表明节肢动物头区化过程包括复合型头区形成和口后附肢特异化两个独立事件。其中复合型头区形成经历了原头、原复合头和真复合头3个演化阶段。节肢动物原头只有口前两个相互独立的体节,后来通过躯干体节向前端归并形成具有3个或3个以上口后头区体节的复合型头区;但头区腹部口后附肢特异化事件显然滞后于背部体节的愈合,头区口后附肢形态特异化事件是在复合型头区形成之后,节肢动物所面临的又一个漫长的演化过程。文中尝试结合发育生物学研究进展分析节肢动物头区化过程的分子机制。认为原躯干前端体节发育机制的改变和Hox基因的头/躯干分区表达导致节肢动物复合型头区的发生;而头区口后特异性附肢出现与Hox基因表达区域及其功能的体节特异化事件有关。Recently studies of the Maotianshan fauna show that the arthropod pro-cephalon initially contains two separate segments (i.e. the eye-bearing segment and the antennal segment), which fuses with the succeeding trunk tergites to form the syncephalon with three or more post-oral segments. Then the diversification of head appendages occurs, which leads towards the specific mouthparts of extant arthropods. So the cephalization of arthropods at least includes two stages: the formation of syncephalons and the specification of head pro-oral appendages. The present study tries to under-stand the interplay between the developmental mecha-nism and morphological changes in the origin and evolution of arthropod head. It seems possible that the changes of developmental mechanism in the anterior trunk segments involve in the changes of trunk-to-head segments in the formation of syncephalons, and that the Hox genes expression in fine segment-specific domains and/or fractional functions of multiple Hox genes are referred to the specification of individual segments. One of the reasonable explanations for the hysteresis of appendages diversification against the fusion of dorsal segments in arthropods head is that different developmental mechanism (e.g. different Hox genes) underlies the formation of different parts in the same segments.

关 键 词：节肢动物 机制分析 起源 复合型 发育生物学 HOX基因 独立事件 演化阶段 相互独立 演化过程 分子机制 研究进展 发育机制 基因表达 异化 附肢 动物群 躯干 特异性 

分 类 号：Q915[天文地球—古生物学与地层学]