Howell N, Halvorson S, Kubacka I, McCullough D A, Bindoff L A, Turnbull D M
Department of Radiation Therapy, University of Texas Medical Branch, Galveston 77550.
Hum Genet. 1992 Sep-Oct;90(1-2):117-20. doi: 10.1007/BF00210753.
The segregation of a heteroplasmic silent polymorphism in the mitochondrial ND6 gene has been followed in a human maternal lineage comprising eight individuals and spanning three generations. Heteroplasmy persisted in all eight maternally related family members. More importantly, the frequencies of the two alleles showed relatively little variation among individuals or between generations. In contrast to the findings in other mammalian lineages, the present results indicate relatively slow mitochondrial gene segregation. A narrow bottleneck in the number of mitochondrial DNA (mtDNA) molecules, which occurs at some stage of oogenesis, has been advanced to explain rapid mammalian mitochondrial gene segregation. It is suggested here that the segregation of mitochondrial genes may be more complex than initially envisaged, and that models need to be developed that account for both rapid and slow segregation. One possibility, which reconciles both physical and genetic studies of mammalian mtDNA, is that the unit of mitochondrial segregation is the organelle itself, each containing multiple mtDNA molecules.
在一个包含八个人、跨越三代的人类母系谱系中，对线粒体ND6基因中异质性沉默多态性的分离情况进行了追踪。异质性在所有八个母系相关家庭成员中持续存在。更重要的是，两个等位基因的频率在个体之间或代际之间显示出相对较小的变化。与其他哺乳动物谱系的研究结果相反，目前的结果表明线粒体基因分离相对缓慢。有人提出，在卵子发生的某个阶段出现的线粒体DNA（mtDNA）分子数量的狭窄瓶颈，可以解释哺乳动物线粒体基因的快速分离。这里表明，线粒体基因的分离可能比最初设想的更为复杂，需要开发能够解释快速和缓慢分离的模型。一种能够协调哺乳动物mtDNA的物理和遗传研究的可能性是，线粒体分离的单位是细胞器本身，每个细胞器都包含多个mtDNA分子。
