【摘要】 神经突起生长导向因子(Netrin)蛋白家族是分泌型蛋白质,其通过与不同的受体相互作用,在神经发育过程中起轴突导向和细胞迁移中发挥着双重导向功能.本文分别对涉及到细胞相互作用的Netrin基因家族的起源与进化进行研究.以进化史不同阶段的代表物种作为研究对象,通过使用MEGA的邻接法和似释然法分别对Netrin基因家族构建系统发育树;使用PAML 4.7工具以核苷酸序列作为分析材料进行选择压分析,筛选出发生正选择作用的位点;使用DIVERGE3.0软件对Netrin氨基酸序列进行功能分化分析,筛选出Ⅰ型和Ⅱ型功能分化位点.更多还原

【Abstract】 Netrins are a class of secretory proteins involved in axon guidance.Netrins are chemotropic;agrowing axon will either move towards or away from a higher concentration of Netrin,which involved in different acceptors.This paper studies the evolutionary history of Netrin gene family with the sequences of representative species.Phylogenetic trees were constructed by using Neighbor-Joining and Maximum Likelihood methods.The analysis of selection pressure was performed by PAML4.7tool for detecting positive selected sites.Except these,the function diversity of Netrins was also analysized by using DIVERGE3.0software,the functional divergence sites of TypeⅠ and TypeⅡin Netrin were screened out.更多还原