MacNeil Donna, Strobeck Curtis
Department of Zoology, University of Alberta, Edmonton, AB, T6G 2E9, Canada.
Evolution. 1987 Jul;41(4):873-881. doi: 10.1111/j.1558-5646.1987.tb05860.x.
Mitochondrial DNA (mtDNA) from 71 Columbian ground squirrels (Spermophilus columbianus) collected in 12 locations in western Canada were assayed for restriction-site variation with 10 endonucleases. Five of these endonucleases revealed variant patterns, and the composite genotypes were used to develop a linear transformation series among the mtDNA genotypes. Two of the four clones had a wide distribution, while the remaining two clones were geographically restricted. The mtDNA of Columbian ground squirrels was also compared to two other species of Sciuridae: Richardson's ground squirrels (S. richardsonii) and Arctic ground squirrels (S. parryii). Calculation of divergences from fragment length and restriction-site data indicated that Arctic ground squirrels and Richardson's ground squirrels were more closely related to each other than either was to Columbian ground squirrels. The transformation series among clones within the Columbian ground squirrels was rooted using Richardson's and Arctic ground squirrels as out-groups. From these data, we conclude that the colonization by female founders of Columbian ground squirrel populations occurred after deglaciation along the eastern ranges of the Rocky Mountains, while colonies on the western ranges may have been present before extensive deglaciation occurred, having existed in refugia in northwestern Alberta.
对从加拿大西部12个地点采集的71只哥伦比亚地松鼠（Spermophilus columbianus）的线粒体DNA（mtDNA），用10种内切酶检测其限制性位点变异。其中5种内切酶显示出变异模式，复合基因型被用于构建mtDNA基因型之间的线性转化系列。4个克隆中有2个分布广泛，其余2个克隆受地理限制。还将哥伦比亚地松鼠的mtDNA与松鼠科的另外两个物种进行了比较：理查森地松鼠（S. richardsonii）和北极地松鼠（S. parryii）。根据片段长度和限制性位点数据计算的分歧表明，北极地松鼠和理查森地松鼠之间的亲缘关系比它们与哥伦比亚地松鼠的关系更近。以理查森地松鼠和北极地松鼠作为外群，构建了哥伦比亚地松鼠内克隆之间的转化系列。从这些数据中，我们得出结论，哥伦比亚地松鼠种群的雌性奠基者的定殖发生在落基山东部山脉冰消之后，而西部山脉的种群可能在广泛冰消之前就已存在，曾在艾伯塔省西北部的避难所中生存。
