Wyttenbach A, Borodin P, Hausser J
Institut of Zoology and Animal Ecology, University of Lausanne, Lausanne, Switzerland.
Cytogenet Cell Genet. 1998;83(3-4):199-206. doi: 10.1159/000015178.
Meiotic drive has attracted much interest because it concerns the robustness of Mendelian segregation and its genetic and evolutionary stability. We studied chromosomal meiotic drive in the common shrew (Sorex araneus, Insectivora, Mammalia), which exhibits one of the most remarkable chromosomal polymorphisms within mammalian species. The open question of the evolutionary success of metacentric chromosomes (Robertsonian fusions) versus acrocentrics in the common shrew prompted us to test whether a segregation distortion in favor of metacentrics is present in female and/or male meiosis. Performing crosses under controlled laboratory conditions with animals from natural populations, we found a clear trend toward a segregation distortion in favor of metacentrics during male meiosis, two chromosome combinations (gm and jl) being significantly preferred over their acrocentric homologs. Apart for one Robertsonian fusion (hi), this trend was absent in female meiosis. We propose a model based on recombination events between twin acrocentrics to explain the difference in transmission ratios of the same metacentric in different sexes and unequal drive of particular metacentrics in the same sex. Pooled data for female and male meiosis revealed a trend toward stronger segregation distortion for larger metacentrics. This is partially in agreement with the frequency of metacentrics occurring in natural populations of a chromosome race showing a high degree of chromosomal polymorphism.
减数分裂驱动引起了人们的广泛关注，因为它涉及孟德尔分离的稳健性及其遗传和进化稳定性。我们研究了普通鼩鼱（Sorex araneus，食虫目，哺乳动物）的染色体减数分裂驱动，它表现出哺乳动物物种中最显著的染色体多态性之一。普通鼩鼱中着丝粒染色体（罗伯逊融合）与近端着丝粒染色体进化成功的开放性问题促使我们测试在雌性和/或雄性减数分裂中是否存在有利于着丝粒染色体的分离畸变。在可控实验室条件下，用来自自然种群的动物进行杂交，我们发现雄性减数分裂过程中明显存在有利于着丝粒染色体的分离畸变趋势，两种染色体组合（gm和jl）比它们的近端着丝粒同源染色体更受青睐。除了一种罗伯逊融合（hi）外，雌性减数分裂中没有这种趋势。我们提出了一个基于双近端着丝粒之间重组事件的模型，以解释同一着丝粒染色体在不同性别中传递比率的差异以及同一性别中特定着丝粒染色体的不等驱动。雌性和雄性减数分裂的汇总数据显示，较大着丝粒染色体的分离畸变趋势更强。这与一个显示高度染色体多态性的染色体族自然种群中着丝粒染色体出现的频率部分一致。
