Densmore Llewellyn D, Moritz Craig C, Wright John W, Brown Wesley M
Laboratory of Molecular Systematics, Museum of Zoology, and Department of Biology, University of Michigan, Ann Arbor, MI, 48109-1079.
Section of Herpetology, Natural History Museum of Los Angeles County, Los Angeles, CA, 90007.
Evolution. 1989 Aug;43(5):969-983. doi: 10.1111/j.1558-5646.1989.tb02543.x.
Mitochondrial DNAs (mtDNAs) from nine morphologically distinct unisexual species and five bisexual species of lizards, all from the sexlineatus species-group of Cnemidophorus, were compared using restriction endonucleases. The unisexual lizards have mtDNAs that are identical at all or nearly all of the 128 sites cleaved. Although differing little in sequence, some mtDNAs differed in size due to the presence of tandem sequence duplications. Phylogenetic analysis of cleavage maps indicates that the mtDNAs of the unisexuals are most similar to that of the bisexual species C. inornatus. Considerable mtDNA diversity exists among C. inornatus populations, and one geographically restricted subspecies, C. i. arizonae, was identified as the most probable maternal ancestor of all nine unisexuals. All but one of these are triploid, and all have at least one C. inornatus gene complement. This, together with the homogeneity of their mtDNAs, suggests that all stem from one or a small number of allodiploid females (presumably parthenogenetic) that originated in a restricted geographic area in the recent past. These data, when combined with those from allozyme studies, preclude the possibility that most of the triploid unisexuals could have arisen via fertilization of an unreduced diploid ovum from one species by a haploid sperm from a different species.
利用限制性内切酶对来自Cnemidophorus属性线纹物种组的9个形态各异的单性蜥蜴物种和5个两性蜥蜴物种的线粒体DNA（mtDNA）进行了比较。这些单性蜥蜴的mtDNA在128个被切割位点上全部或几乎全部相同。尽管序列差异不大，但由于存在串联序列重复，一些mtDNA在大小上有所不同。切割图谱的系统发育分析表明，单性蜥蜴的mtDNA与两性物种C. inornatus的最为相似。C. inornatus种群中存在相当大的mtDNA多样性，一个地理分布受限的亚种C. i. arizonae被确定为所有9个单性蜥蜴最可能的母系祖先。除其中一个外，其他所有单性蜥蜴都是三倍体，并且都至少有一个C. inornatus基因互补组。这一点，再加上它们mtDNA的同质性，表明所有单性蜥蜴都起源于近期一个或少数几个（推测为孤雌生殖的）异源二倍体雌性，这些雌性起源于一个受限的地理区域。这些数据与等位酶研究的数据相结合，排除了大多数三倍体单性蜥蜴是由一个物种未减数的二倍体卵子被另一个物种的单倍体精子受精产生的可能性。
