【摘要】 以线粒体细胞色素b基因序列(Cyt b)为分子标记,结合系统发育分析(最大似然法和贝叶斯法)和遗传距离统计(JC遗传距离模型)等方法,分析青藏高原东部地区田鼠类动物的物种组成和地理分布特征。从16个样点共采集到189个田鼠样品,成功获得所有个体的Cyt b全序列,长度为1 143 bp,共检测到248个变异位点和65个单倍型。系统发育分析显示,最大似然树和贝叶斯树的结构基本一致,将65个单倍型分为3组(G1-G3),分别与已知的柴达木根田鼠(Microtus limnophilus)、青海松田鼠(Neodon fuscus)和高原松田鼠(N.irene)聚为单系群,支持率都为100%。遗传距离统计显示,G1、G2、G3组内两两单倍型之间的遗传距离范围分别为0.09%-3.04%、0.09%-0.70%、0.18%-1.95%;同时,G1与柴达木根田鼠参考序列之间、G2与青海松田鼠参考序列之间、G3与高原松田鼠参考序列之间遗传距离范围分别为0.61%-2.49%、0.53%-0.97%、1.77%-2.22%。结合系统发育和遗传距离分析结果,本研究中采集到的田鼠个体可以鉴定为3个物种:柴达木根田鼠(n=135)、青海松田鼠(n=30)和高原松田鼠(n=24)。其中,柴达木根田鼠分布最广(10个地点),青海松田鼠(4个地点)和高原松田鼠(3个地点)的分布区则相对狭小;3种动物在分布区上重叠度很小,仅河南县同时发现有柴达木根田鼠和青海松田鼠分布。研究表明,青藏高原东部地区至少有3种田鼠分布,种间遗传界限清晰,空间分布具有一定规律性。研究结果为了解青藏高原东部地区田鼠类动物的物种分布提供可靠的基础资料,同时为这一地区的田鼠类动物的分子鉴定方法提供参考。更多还原

【Abstract】 Using mitochondrial cytochrome b gene(Cyt b) as a molecular marker combined with phylogenetic methods(Maximum Likelihood and Bayesian Inference) and genetic distance statistics(Jukes and Cantor’s distance),we analyzed the species composition and geographical distribution of voles in the east of the Qinghai-Tibet Plateau.We sampled 189 voles from 16 localities and sequenced the complete Cyt b sequences(1 143 bp) of these individuals.A total of 248 variable sites and 65 haplotypes were detected.The topology of Maximum Likelihood and Bayesian Inference trees were basically consistent,clustering the 65 haplotypes into three groups(G1-G3),respectively forming three monophyletic groups with known Microtus limnophilus,Neodon fuscus and N.Irene,and with very high bootstrap support values(100%).The haplotype based pairwise genetic distances within G1,G2,G3 were respectively 0.09%-3.04%,0.09%-0.70% and0.18%-1.95%;while between G1 and M.limnophilus,between G2 and N.fuscus and between G3 and N.Irene were0.61%-2.49%,0.53%-0.97% and 1.77%-2.22%,respectively.Based on phylogenetic and genetic distance analyses,these voles were identified as three species:M.limnophilus(n = 135),N.fuscus(n = 30) and N.irene(n = 24).M.limnophilus was most widely distributed(10 localities) while N.fuscus(4 localities) and N.irene(3 localities) were confined to small ranges.The overlapping areas of these three species was small.Only one locality(HN) was inhabited byM.limnophilus and N.fuscus at the same time.Our results showed that there were at least three vole species distributed in the study regions.They were well defined by molecular marker and had certain regularity in the geographical distribution patterns.Our results provide fundamental information of vole distribution in the east of the Qinghai-Tibet Plateau as well as an example for molecular identification of rodents in the study regions.更多还原