东湖天蓝喇叭虫(Stentor coeruleus)种群的离散分化

利用筛选的12条10 bp的随机引物对采自武汉市东湖(3个样点)、南湖(3个样点)、月湖(1个样点)和关桥(1个样点)四个水体的天蓝喇叭虫(Stentor coeruleus)种群进行了随机扩增多态DNA(RAPD)研究,所得清晰条带显示不同样点样本之间存在着一定的变异,其遗传距离在0.076-0.416之间.用Rapdistance 1.04构建聚类图并探讨不同样点之间的遗传距离远近.结果显示南湖的3样点的遗传距离较近,在聚类图上聚成一枝,应该为同一个种群;而东湖的3个样点可能是由于地理隔离原因,在聚类图上有2个样点聚成一枝,而另1个样点被其他样点所分隔,不属于同一个种群.这种现象的发现从实例上支持了生物地理学关于物种形成的离散假说.更有意义的是本研究可启动水体微生物种群分化和物种形成及过渡的研究,并期望促进种群生态学方面的研究和谱系生物地理学及离散分化生物地理学的发展.

The population vicariance of Stentor coeruleus in Lake Donghu, Wuhan

Random amplified polymorphic DNA(RAPD) markers were applied to analyze genetic relationships of Stentor coeruleus that were sampled from four water areas including Lake Donghu (D.Lake),Lake Nanhu (N. Lake),Lake Yuehu (Y.Lake) and Pond Guanqiao (G.Pond).Their Genomes were amplified with 12 random primers.Distinctly different banding patterns were obtained,with which the genetic relationship of organisms trea- ted was deduced:the genetic distance among the sample was 0.076-0.416.The phylogenetic tree was constructed by Rapdistance 1.04.The results showed that three samples from N.Lake clustered into one branch which indica- ted S.coeruleus in the lake belong to one population,but 3 samples from D.Lake were separated by the sample from G.Pond which showed that S.coeruleus in it belong to different populations.This discovery supported the hy- pothesis of vicariance in geographic.It will promote the researches on the population ecology of micro-hydrobiont, and the development of phylogeography and vicariance biogeography.