黑腹果蝇种组组蛋白基因间内含子区的分子进化

通过分析黑腹果蝇种组(Drosophila melanogasterspecies group)9个种亚组代表种和D.pseudoobscura的组蛋白基因H2A和H2B的内含子的碱基组成、替换速率、转换/颠换比、二级结构和系统发育关系等发现:整个序列长度变异范围在201 bp(ficusphila)到232 bp(takahashii)之间,替换速率为0.82,转换明显高于颠换,内含子和外显子结合区不遵循“GT-AG”和“AT-AC”模式,而是“TT-AG”模式,二级结构与系统分化关系具有相关性.我们认为组蛋白基因H2A和H2B的内含子是先起源的,在进化过程中由于承受的选择压力不同而发生了变异.

Molecular evolution of intron in histone genes in Drosophila melanogaster species group

The debates of the origin and evolutionary mechanics of introns remain to be controversial,we have investigated the nucleotide sequences of introns of histone gene pair H2A-H2B of the 9 species subgroup in Drosophila melanogaster species group and the D.pseudoobscura in obscura group.The results of analysis of base composition,substitution rate,evolution distance,ratio of translation to tranversition,secondary structure,and phylogenetic relationships show that variation of the total length of these introns was from 201?bp(ficusphila)to 232?bp(takahashii),substitution rate was 0.82,the values of translation was higher than the values of tranversition,and the conserved boundary regions of intron and exon broken the traditional the"GT-AG" and"AT-AC" models was another new model "TT-AG".The evolutionary of the secondary structures were related to the phylogenetic relations.All the results show that the intron origin early and endured some evolution pressures.