萼花臂尾轮虫种复合体遗传分化的空间格局  

Spatial Patterns of Genetic Differentiation in Brachionus calyciflorus Species Complex

作　　者：项贤领[1] 席贻龙[1] 温新利[1] 张晋艳[1] 马芹[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：《Zoological Research》2010年第3期205-220,共16页动物学研究（英文）

基　　金：国家自然科学基金(30770352;30499341);安徽省优秀青年基金(08040106904);安徽省教育厅自然科学基金(KJ2009B089Z);"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;安徽师范大学青年基金资助项目(2008xqn71)

摘　　要：对采自中国东部8个地理区域中的萼花臂尾轮虫种复合体(Brachionus calyciflorus species complex)内124个轮虫克隆的核DNA ITS区进行了测序和分析,重建了萼花臂尾轮虫种复合体的系统发生树。研究发现,73个单倍型聚合为3个支系,支系间序列差异百分比为4.2%～25.3%,表明萼花臂尾轮虫实际上是由3个隐种组成的种复合体,在广州、儋州和芜湖采样点均具有隐种共存现象。萼花臂尾轮虫种复合体的核苷酸多样性和单倍型多样性均较高,隐种Ⅲ内各种群间遗传分化指数也较高,这可能是由于栖息地片段化和有限的基因流导致的。另外在冰期瓶颈后拓殖种群的快速增长也阻碍了有效基因流,并加速了地理种群间的遗传分化。巢式支系分析显示部分巢支具有一定的系统地理格局,而Mantel检验表明,种群间平均净遗传距离及遗传分化指数和地理距离间均无显著相关性。末次盛冰期之后的新仙女木事件(Younger Dryas Event,YD)可能对我国萼花臂尾轮虫隐种的分布和地理格局造成较大影响。在YD时期,3个萼花臂尾轮虫隐种可能退缩并共存于南岭以南地区的多个残遗种避难所,而此后的休眠卵长距离拓殖并伴随后期的栖息地片段化可能是形成当前地理格局的主要原因。萼花臂尾轮虫种复合体在全球范围内的地理分布可能与大陆板块构造运动有关。To understand spatial patterns of genetic differentiation in the Brachionus calyciflorus species complex, the rDNA ITS regions of 124 rotifer clones collected from eight geographic regions in East China were sequenced and analyzed. A total of 73 haplotypes were defined, and were grouped into three clades by the phylogenetic trees. The divergences of ITS sequence among the three clades ranged from 4.2% to 25.3%, indicating the occurrence of three cryptic species （cryptic species Ⅰ, cryptic species Ⅱ and cryptic species Ⅲ）. The sympatric co-occurrence of these cryptic species was observed at Guangzhou, Danzhou and Wuhu. The nucleotide diversity in B. calyciflorus complex was higher, and so was haplotype diversity. Within cryptic species III, the higher genetic differentiation might be attributed to fragmentation and restricted gene flow. In addition, the rapid increase of colonizers after an ambiguous glacial bottleneck might interfere with effective gene flow and accelerate genetic differentiation of geographic populations. The nested clade analysis suggested to some extent the geographic structure, and the non-significant correlation existed between the geographic distance and the average pairwise difference between populations （Da） as well as Fst. The Younger Dryas （YD）Event after the last full glacial period might has considerable effect on the patterns of geographic structure and distribution of cryptic B. calyciflorus species. During the YD event, the three cryptic species probably retreated and co-occurred in multiple relict refugia to the south of Nanling area. Long-distance colonization possibly coupled with subsequent fragmentation might be the main reason of the current patterns of geographic structure. The geographic distribution of B. calyciflorus complex on a global scale might be attributed to the motion of continental plates.

关 键 词：萼花臂尾轮虫 种复合体 遗传分化 空间格局 巢式支系分析 系统地理学 

分 类 号：Q953[生物学—动物学]