Variation and Evolution of the Meiotic Requirement for Crossing Over in Mammals.
Variation and Evolution of the Meiotic Requirement for Crossing Over in Mammals.
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减数分裂要求在哺乳动物中交叉的变化和演变。
DOI：
10.1534/genetics.116.192690
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发表时间：
2017-01
期刊：
影响因子：
3.3
通讯作者：
Dumont BL
中科院分区：
文献类型：
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作者：
Dumont BL
第一次减数分裂时同源染色体的分离取决于每条染色体至少存在一个位置良好的交换。然而，在一些哺乳动物物种中，交换的基因组分布符合每个染色体臂一次交换的更严格的基线要求。鉴于交叉的减数分裂要求定义了产生可行配子所需的最小重组频率，因此确定此约束的染色体规模对于定义易发生非整倍性的交叉特征和了解影响跨物种重组率进化模式的参数至关重要。在这里，我使用细胞遗传学方法对核型多样化的家鼠（家鼠）和田鼠（田鼠属）的交叉进行原位成像，以测试染色体数量和配置如何限制基因组中交叉的分布。我表明，家鼠中交换的全局分布以每个染色体臂至少一次交换为阈值，而田鼠的交换景观则由每条染色体一次交换的更宽松的要求来定义。我在对 112 个哺乳动物物种已发表的重组和核型数据进行进化荟萃分析时扩展了这些发现，并证明基因组交叉分布的物理规模在哺乳动物进化过程中经历了多次独立的转变，从每条染色体臂一次交叉到每条染色体一次。总之，这些结果表明，染色体规模对交叉率的限制本身就是物种间进化的一个特征，这一发现揭示了哺乳动物交叉率变异的重要来源。
The segregation of homologous chromosomes at the first meiotic division is dependent on the presence of at least one well-positioned crossover per chromosome. In some mammalian species, however, the genomic distribution of crossovers is consistent with a more stringent baseline requirement of one crossover per chromosome arm. Given that the meiotic requirement for crossing over defines the minimum frequency of recombination necessary for the production of viable gametes, determining the chromosomal scale of this constraint is essential for defining crossover profiles predisposed to aneuploidy and understanding the parameters that shape patterns of recombination rate evolution across species. Here, I use cytogenetic methods for in situ imaging of crossovers in karyotypically diverse house mice (Mus musculus domesticus) and voles (genus Microtus) to test how chromosome number and configuration constrain the distribution of crossovers in a genome. I show that the global distribution of crossovers in house mice is thresholded by a minimum of one crossover per chromosome arm, whereas the crossover landscape in voles is defined by a more relaxed requirement of one crossover per chromosome. I extend these findings in an evolutionary metaanalysis of published recombination and karyotype data for 112 mammalian species and demonstrate that the physical scale of the genomic crossover distribution has undergone multiple independent shifts from one crossover per chromosome arm to one per chromosome during mammalian evolution. Together, these results indicate that the chromosomal scale constraint on crossover rates is itself a trait that evolves among species, a finding that casts light on an important source of crossover rate variation in mammals.