轮虫同域性物种形成:来自萼花臂尾轮虫克隆间的分子系统发育关系和生殖隔离的证据  

Sympatric speciation in rotifers:evidence from molecular phylogenetic relationships and reproductive isolation among Brachionus calyciflorus clones

作　　者：李化炳[1] 席贻龙[1] 程新峰[1] 项贤领[1] 胡存兵[1] 陶李祥[1] 

机构地区：[1]安徽师范大学生命科学学院,安徽省高校生物环境与生态安全省级重点实验室,安徽芜湖241000

出　　处：《动物学报》2008年第2期256-264,共9页ACTA ZOOLOGICA SINICA

基　　金：国家自然科学基金(No.30770352;No.30270221;No.30499341);安徽省优秀青年基金(No.04043050);安徽省高校生物环境与生态安全省级重点实验室专项基金(No.2004sys003);重要生物资源保护和利用研究安徽省重点实验室专项基金资助项目~~

摘　　要：对采自芜湖市三个不同水体中的萼花臂尾轮虫(Brachionus calyciflorus)17个克隆的线粒体COⅠ基因和rDNAITS1序列进行的分析结果表明:萼花臂尾轮虫不同克隆间COⅠ基因序列差异百分比为0-14.0%,平均为5.1%;ITS1序列差异百分比为0-7.4%,平均为2.2%。基于COⅠ基因序列构建的分子系统树(NJ树、MP树、ML树和贝叶斯树)均支持将17个克隆划分为三个姐妹种,各姐妹种间的序列差异百分比为7.2%-14.0%。基于ITS1序列构建的同样四种分子系统树也支持将17个克隆划分为三个姐妹种,但其中的克隆HE5在姐妹种中的归属与基于COⅠ基因序列构建的分子系统树所得出的结果不同,各姐妹种间的序列差异百分比为1.9%-7.4%。混交雌体和雄体间的交配实验结果表明,轮虫各姐妹种间存在着明显的生殖隔离,克隆HE5在姐妹种中的归属应与基于COⅠ基因序列构建的分子系统树所得出的结果一致;ITS1序列进化速率较低,不宜用于轮虫姐妹种的准确甄别。COⅠ基因进化钟计算结果显示,三个姐妹种间,克隆LE9所属的姐妹种早在8百万年前便分化形成出来,HE1、HE2、HE4-7所属的姐妹种于5百万年前分化产生。The mtDNA CO Ⅰ gene and rDNA ITS1 region of 17 Brachionus calyciflorus clones from three water bodies in Wuhu city were sequenced and analyzed, and their molecular phylogenetic trees were constructed by Neighbor-Joining （NJ）, Maximum- Parsimony （MP）, Maximum-Likelihood （ML） and Bayesian methods using B. patu/us as an outgroup. The results showed that the percentage of sequence divergence in 17 samples is from 0% to 14.0% （ mean 5.1% ） for the CO Ⅰ gene, and from 0% to 7.4% （mean 2.2% ） for the rDNA ITS1. All the phylogenetic trees based on CO Ⅰ gene sequence showed that three sibling species existed in the 17 samples with 7.2% - 14.0% sequence divergence among them. Similarly, all the phylogenetic trees based on the ITS1 sequence also indicated that three sibling species exited in the 17 samples with 1.9% - 7.4% sequence divergence among them, but differently in positioning clone HE5. Cross-mating tests demonstrated reproductive isolation between all the three sibling species in the B. calyciflorus species complex. The position of clone HE5 was identical to that of the phylogenetic trees based on the CO Ⅰ gene sequence. The evolutionary rate of the ITSI is slower and unsuitable to accurately identify sibling species in this rotifer species complex. The molecular calculation based on the CO Ⅰ gene showed that the sibling species with clone HE5 as a representative diverged 8 million years ago, and that represented by clone HEI, HE2 and HE4-7 5 million years ago

关 键 词：萼花臂尾轮虫 姐妹种 COⅠ基因序列 rDNA ITS1序列 生殖隔离 

分 类 号：Q953[生物学—动物学]