PDF(Pubmed)
Abstract：
Robertsonian translocation is the most common chromosomal rearrangement in mammals, and represents the type of chromosomal change that most effectively contributes to speciation in natural populations. Rb translocations involve double-strand DNA breaks at the centromere level in two telocentric chromosomes, followed by repair ligation of the respective long arms, creating a metacentric Rb chromosome. Many different chromosomal races have been described in Mus musculus domesticus that show reduced chromosome numbers due to the presence of Rb metacentric chromosomes. The crossroads between ancestral telocentrics and the new metacentric chromosomes should be resolved in the meiotic cells of the heterozygote individuals, which form trivalents. The preferential segregation of metacentric chromosomes to the egg during female meiosis I has been proposed to favor their fixation and eventual conversion of a telocentric karyotype to a metacentric karyotype. This biased segregation, a form of meiotic drive, explains the karyotype changes in mammalian species that have accumulated Rb fusions. We studied and compared the number of Rb chromosomes inherited by the offspring of multiple Rb heterozygous of M. domesticus in reciprocal crosses. We did not find that the Rb chromosomes were inherited preferentially with respect to the telocentric chromosomes; therefore, we found no evidence for the meiotic drive, nor was there a random distribution of Rb chromosomes inherited by the descendants.
摘要：
罗伯逊易位是哺乳动物中最常见的染色体重排,并且代表了最有效地促进自然种群物种形成的染色体变化类型。Rb易位涉及两条端粒染色体着丝粒水平的双链DNA断裂，然后修复各自的长臂结扎，创造了一个亚中心的Rb染色体.在家蚕中已经描述了许多不同的染色体种族，由于Rb中心染色体的存在，它们显示出染色体数量减少。应在杂合子个体的减数分裂细胞中解决祖先端粒和新的中心染色体之间的十字路口，形成三元。已提出在雌性减数分裂I期间将中心染色体优先分离到卵中，以有利于它们的固定和最终将中心核型转化为中心核型。这种有偏见的隔离，减数分裂的一种形式,解释了积累Rb融合的哺乳动物物种的核型变化。我们研究并比较了家蝇多个Rb杂合后代在相互杂交中遗传的Rb染色体数量。我们没有发现Rb染色体相对于端心染色体优先遗传；因此，我们没有发现减数分裂的证据,后代遗传的Rb染色体也没有随机分布。
