Dating the genetic bottleneck of the African cheetah.
Dating the genetic bottleneck of the African cheetah.
复制标题
DOI：
10.1073/pnas.90.8.3172
复制
发表时间：
1993-04
影响因子：
11.1
通讯作者：
M. Menotti-Raymond;Stephen J. O'Brien
中科院分区：
文献类型：
--
作者：
M. Menotti-Raymond;Stephen J. O'Brien
猎豹是不寻常的领域中表现出近遗传均匀性在各种位点以前筛选衡量人口遗传多样性。据推测，人口崩溃或人口瓶颈，在最近的历史上的物种是因果关系的核编码基因座观察到的单态配置文件。瓶颈的时间很难评估，但猎豹自然史的某些方面表明它可能发生在最后一个冰河时代（更新世晚期，大约10，000年前）的末期，当时几个大陆上发生了大型脊椎动物的显着灭绝。为了进一步确定这样一个瓶颈的时间，遗传多样性的两个快速演变的DNA序列，线粒体DNA和高变小卫星位点的字符，进行了检查。中等水平的遗传多样性，观察到这两个指数在调查的两个猎豹亚种，一个来自南非，一个来自东非。根据观察到的VNTR（可变数目的串联重复序列）基因座和线粒体DNA的突变率，从DNA多样性积累的程度反向计算支持一个假设，即古更新世的瓶颈，使猎豹在核编码基因座的遗传变异中表现出不稳定性，但会有足够的时间部分重建更迅速演变的基因组DNA片段。
The cheetah is unusual among fields in exhibiting near genetic uniformity at a variety of loci previously screened to measure population genetic diversity. It has been hypothesized that a demographic crash or population bottleneck in the recent history of the species is causal to the observed monomorphic profiles for nuclear coding loci. The timing of a bottleneck is difficult to assess, but certain aspects of the cheetah's natural history suggest it may have occurred near the end of the last ice age (late Pleistocene, approximately 10,000 years ago), when a remarkable extinction of large vertebrates occurred on several continents. To further define the timing of such a bottleneck, the character of genetic diversity for two rapidly evolving DNA sequences, mitochondrial DNA and hypervariable minisatellite loci, was examined. Moderate levels of genetic diversity were observed for both of these indices in surveys of two cheetah subspecies, one from South Africa and one from East Africa. Back calculation from the extent of accumulation of DNA diversity based on observed mutation rates for VNTR (variable number of tandem repeats) loci and mitochondrial DNA supports a hypothesis of an ancient Pleistocene bottleneck that rendered the cheetah depauperate in genetic variation for nuclear coding loci but would allow sufficient time for partial reconstitution of more rapidly evolving genomic DNA segments.