中文摘要：

研究了青海沙蜥红原亚种（Phrynocephalus vlangalii hongyuanensis）分布于四川若尔盖辖曼（XM）、红原（HY）和甘肃玛曲（MQ）这3个地理单元7个居群的ND4-tRNA^leu基因的序列变异和遗传多样性。72个序列比对得到785bp的片断，含变异位点7个，定义了9种单倍型。结果显示7个居群总的核苷酸多样性较低（0．00231±0．00016），单倍型多样性较高（0．806±0．024）；就单个居群而言，MQa、MQb、XMb的遗传多样性低，XMc相对较高。各居群间的Kimura双参数遗传距离小（0．001—0．005），最大遗传距离出现在MQa和XMa之间，XM单元各居群之间遗传距离最小。但分子变异分析（AMOVA）显示3个单元间出现了显著差异（P〈0．01），遗传变异主要存在于地理单元间，占62．61％。除MQ单元形成一支，单倍型网络图没有显示出单倍型和地理位置的对应关系，XM各居群以及HY混杂在一起。XM单元单倍型的不配对分布（Mismatch distribution）为明显左移的单峰，同时Fu’s Fs test得到负值（Fs=-2．21937），这都暗示XM单元可能经历了近期种群扩张，这是其单倍型多样性较高和核苷酸多样性较低的原因。MQ单元遗传多样性低而与其他单元显著分化，推测与黄河在若尔盖玛曲之间贯通有关。近期沼泽的形成对XMb的隔离时间短，使得其遗传多样性低但还不足以形成大的遗传差异。

英文摘要：

According to the distribution of Phrynocephalus vlangalii hongyuanensis in Zoige Wetland, three geographic units： Zoige Xiaman （XM）, Hongyuan （HY）, both in Sichuan Province and Maqu （MQ） in Gansu Province were defined. We used molecular methods to reveal these unit＇s genetic variation and diversity. A 785bp fragment of the mtDNA ND4-tRNA^leu was determined from 72 samples in seven populations of P. vlangalii hongyuanensis. Seven variable nucleotide sites and nine haplotypes were identified in the 785bp fragments. As a whole, the haplotype diversity was high （0.806±0.024）, but the nucleotide diversity was low （0.00231±0.00016）. In a single population, MQa, MQb and XMb had very low genetic diversities, and XMc had a much higher one. The Kimura 2-parameter distances among all the populations were small （0.001-0.005）, and the distance between MQa and XMa was the greatest. Analysis of molecular variance （AMOVA） showed that the three units were distinctly different （P〈0.01）, and 62.61% of the total genetic diversity was attributable to variation among units. There were 3 haplotypes shared among XM and HY, and no geographic clustering was observed except MQ from the TCS network. The results from the mismatch distribution analysis and Fu＇s Fs test （Fs=-2.21937） implied that there might be a recent population expansion in the XM unit, and this may be the reason why XM had a high haplotype diversity but a low nucleotide diversity. We estimate that the MQ and XMb have lower diversities because of some very recent geographic events, such as the formation of the Yellow river＇s upriver and the Zoige Wetland. Although they are distinctly different, not enough time has passed for them to have diverged a great genetic distance.