Molecular phylogenetic geography of pan tropic sea dispersed plants : Gene flow and species differentiation through geographic barrier.

泛热带海洋分散植物的分子系统发育地理学：通过地理屏障的基因流和物种分化。

基本信息

批准号：
14405015
负责人：
TATEISHI Yoichi
金额：
$ 8万
依托单位：
University of the Ryukyus
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

项目摘要

Pan tropic sea dispersed plants are widely distributed on the sea coast of the world tropics. Their population genetics were analyzed on many samples gathered from all over the tropics and subtropics to know their differentiation process into species and rates of gene flows between populations to keep the species.A phylogenetic tree constructed using the nucleotide sequences of a c.7,500 bp portion of chloroplast DNA suggested the possibility that recurrent speciation from H.tiliaceus has given rise to all of its allied species. Three major sequence haplotypes of H.tiliaceus had wide and overlapping distributions throughout the Pacific, Atlantic and Indian Ocean regions. Statistical analysis using F_<ST> and AMOVA did not show significant genetic differentiation among the H.tiliaceus populations in the three oceanic regions. These results suggested substantial gene flow occurred between populations in the different oceanic regions due to sea-drifted seeds. A strong genetic difference b … More etween the Pacific and Atlantic populations of H.pernambucensis was observed, which indicates that gene flow in this species between the two regions has been prevented. The wide and dominant distribution of a haplotype shared by H.pernambucensis and H.tiliaceus in the Atlantic region suggests significant introgression between the two species in this region.Ipomoea pes-caprae is divided into two geographical subspecies, subsp.brasiliensis distributed in the world tropics and subsp. pes-caprae of the Indian Ocean. Although both subspecies have sea-dispersed seeds, their distribution ranges are overlapped in the Indian Ocean. By the analysis using AFLP marker the genetic differentiation between these subspecies was clearly observed. Moreover gene flows among distant populations were observed. Geographic distance was slightly correlated with genetic distance.The genus Canavalia consists of about 50 species mostly distributed in the world tropics and subtropics. Among them several species as C.rosea have wide distribution range over the tropics and subtropics. Phylogenetic tree constructed by ITS sequences of nrDNA using extensive samples suggested that the Hawaiian endemic subgen.Maunaloa was derived from C.rosea that migrated to Hawaii by sea-drift dispersal, and loss of sea-drift ability occurred in the speciation process. Less

泛热带海洋分散植物广泛分布于世界热带沿海地区，对从热带和亚热带各地采集的大量样本进行群体遗传学分析，了解其物种分化过程和群体间基因流动速率，以保持其种群遗传特征。使用叶绿体 DNA 的约 7,500 bp 部分的核苷酸序列构建的系统发育树表明，H.tiliaceus 的循环物种形成可能产生了其所有近缘物种。 H.tiliaceus 的三个主要序列单倍型在整个太平洋、大西洋和印度洋区域具有广泛且重叠的分布，使用F_<ST>和AMOVA 的统计分析没有显示这三个海洋区域的H.tiliaceus 种群之间存在显着的遗传分化。这些结果表明，由于海洋漂流的种子，在太平洋和大西洋的H.pernambucensis种群之间观察到了显着的基因流动，这表明该基因。该物种在两个地区之间的流动已被阻止。H.pernambucensis 和 H.tiliaceus 在大西洋地区共享的单倍型的广泛且占优势的分布表明该地区两个物种之间存在显着的基因渗入。Ipomoea pes-caprae 被划分。分为两个地理亚种，subsp.brasiliensis 分布于世界热带地区，subsp.caprae 分布于印度洋。通过使用 AFLP 标记进行分析，可以清楚地观察到这些亚种之间的分布范围存在重叠，而且观察到地理距离与遗传距离略有相关。 Canavalia 属由约 50 个物种组成。主要分布于世界热带和亚热带地区，其中C.rosea等几种物种在热带和亚热带地区分布范围广泛。夏威夷特有亚属 Maunaloa 源自 C.rosea，通过海漂扩散迁移到夏威夷，在物种形成过程中发生了海漂能力的丧失。