西施舌3个群体H2A基因和nad6-nad1片段序列比较研究

摘要

The H2A ORF and its two wings untranslated region ofCoelomactra antiquata planktonic larvae were obtained by splicing EST sequences. Histone PCR primers (Can-H2AF and Can-H2AR) were designed in two wing sequences of the ORF. H2A fragments (including coding and uncoding regions) were amplified and sequenced. The DNA regions between nad6 and nad1 gene were amplified, and the nucleotide sequence divergence of H2A gene andnad6~nad1 fragment was analyzed. We obtained 23 DNA fragments of H2A gene, and the size of the fragments is 606 bp (RZ, BH populations) or 616 bp (ZZ population). Nine kinds of genotypes (Gen) were detected from three populations ofC. antiquata. The AT content (51.51%) of H2A gene in ZZ population is higher than that (50.58%) of RZ and BH populations. H2A gene sequence alignment analysis of nine genotypes showed that there are 616 comparison sites, and the parsimony informative sites accounted for 4.05%. There are 23 variable sites shared by Zhangzhou population, 27 variable sites shared by Beihai and Rizhao populations. The average genetic distance between mixed population and ZZ population was 0.044. It is 0.003 within mixed populations and 0.004 within ZZ population. The genetic distance ratio between intergroup and intrapopulation is 11~14.7; AMOVA analysis showed that there was significant genetic differentiation (FST = 0.937,P<0.01) between Zhangzhou groups and mixed groups (RZ and BH). The cumula 2-parmeter distance ratio interpopulation (Rizhao and Zhangzhou) to intrapopulation based onnad6-nad1is 50~66, it also suggested high level genetic differentiation in Zhangzhou population ofC. antiquata.%西施舌(Coelomactra antiquata)浮游幼虫EST序列拼接获得组蛋白H2A ORF及其两翼的非编码区,在ORF两翼设计引物Can-H2AF和Can-H2AR,扩增H2A基因片段；从nad63′端和nad15′端设计引物,扩增两基因区域DNA序列,测序并进行核苷酸序列差异分析,研究漳州西施舌分化水平。结果：共获得西施舌3个群体H2A基因606bp或616bp基因区DNA片段23条,检测到9种基因型(Gen)。西施舌漳州群体H2A基因AT含量(51.51%)高于日照、北海群体AT含量(50.58%)；序列比对分析显示,简约信息位点占4.05%。基于 H2A基因的漳州群体与日照/北海混合群体间遗传距离平均为0.044,漳州群体,混合群体内遗传距离分别为0.003和0.004,群体间与群体内遗传距离之比为11~14.7； AMOVA分析结果显示,漳州群体和混合群体间发生了极显著遗传分化(FST=0.937, P<0.01)。从nad6~nad1片段中共检出7种单倍型(Hap),漳州群体与日照群体无共享单倍型,基于nad6~nad1的漳州群体与日照群体间遗传距离为0.199~0.202,群体间与群体内遗传距离之比50~66,两个群体间nad1多肽链一级结构存在极大差异,有9个位点的氨基酸不同,日照西施舌缺失6个氨基酸。线粒体DNA显示西施舌漳州与日照群体发生了明显的遗传分化。