通过测定和分析我国新疆乌伦古河流域16只河狸的mt DNA D-loop HV-Ⅰ区序列,对新疆河狸的遗传多样性进行了研究。结果表明,新疆河狸mt DNA D-loop HV-Ⅰ区序列长度为569 bp,A、T、G和C四种核苷酸的平均比例分别为27.0%、32.7%、24.0%和16.2%,新疆河狸mt DNA D-loop HV-Ⅰ区A+T含量高于G+C含量,表现出碱基组成的偏倚性。与蒙古国河狸mt DNA D-loop HV-Ⅰ区(AY623632)比对后,发现我国新疆河狸mt DNA D-loop HV-Ⅰ区10个变异位点,占分析位点总数的2.03%,其中转换位点4个,颠换位点5个,缺失位点1个,无插入位点。依据Gen Bank上已公布的不同地区河狸种群mt DNA D-loop HV-Ⅰ区序列,构建系统树后发现我国新疆河狸和蒙古国河狸位于一个分支,说明两者属于欧亚河狸种下的同一个亚种-蒙新亚种(Castor fiber birulai)。在16只新疆河狸个体中鉴定出2种单倍型,单倍型多样性(Hd)为0.233 00±0.015 78,核苷酸多样性(Pi)为0.001 23±0.015 90,平均核苷酸差异数(K)为0.700,与其他河狸亚种种群比较后发现新疆河狸遗传多样性较低,基因丰富度低,这与新疆河狸局限的生活环境和人为因素的影响是密切相关的。
Genetic diversities of Asiatic beaver(Castor fiber)in Xinjiang was investigated by analyzing the HV-Ⅰsequences of the mitochondrial DNA control region (D-loop)of 16 individuals from the Ulungur watershed of Xinjiang in China.Results showed that the length of mtDNA D-loop HV-Ⅰ sequence of Xinjiang beaver was 569 bp,with nucle-otide frequencies of 27.0%,32.7%,24.0% and 16.2% for A,T,G and C respectively,and the frequencies of A and T was higher than that of G and C,which indicated the preference of nucleotides;that 10 polymorphic sites (2.03% of total analyzed sites) were found in the mtDNA D-loop HV-Ⅰ sequence of Xinjiang beaver compared with that (AY623632)of Mongolia beaver,of which there were four transitions sites,five transversions sites and one missing site;that Xinjiang beaver and Mongolia beaver were in one cluster by phylogenetic analyses based on the open mtDNA D-loop HV-Ⅰ sequence of beaver in other regions on GenBank,suggesting Xinjiang beaver also belonged to the sub-species of C.f.birulai;that Xinjiang beaver population had two unique haplotypes,whose haplotype diversity(Hd), nucleotide diversity(Pi)and average number of nucleotide differences(K)were 0.233 00 ±0.015 78,0.001 23 ±0.015 90 and 0.700,indicating a low level of genetic diversity,deeply related to its limited environment and human factors.