Zetka M
Department of Biology, McGill University, Montreal, Canada.
Genome Dyn. 2009;5:43-55. doi: 10.1159/000166618.
Meiosis in the free-living, hermaphroditic nematode Caenorhabditis elegans is marked by the same highly conserved features observed in other sexually reproducing systems. Accurate chromosome segregation at the meiotic divisions depends on earlier landmark events of meiotic prophase, including the pairing of homologous chromosomes, synapsis between them, and the formation of crossovers. Dissection of these processes has revealed a unique simplification of meiotic mechanisms that impact the interpretation of meiotic chromosome behaviour in more complex systems. Chromosome sites required for chromosome pairing are consolidated to one end of each chromosome, the many sites of recombination initiation are resolved into a single crossover for each chromosome pair, and the diffuse (holocentric) kinetic activity that extends along the length of the mitotic chromosomes is reduced to a single end of each meiotic chromosome. Consequently, studies from the nematode have illuminated and challenged long-standing concepts of homologue pairing mechanisms, crossover interference, and kinetochore structure. Because chromosome pairing, synapsis, and recombination can proceed independently of one another, C. elegans has provided a simplified system for studying these processes and the mechanisms mediating their coordination during meiosis. This review covers the major features of C. elegans meiosis with emphasis on its contributions to understanding essential meiotic processes.
在自由生活的雌雄同体线虫秀丽隐杆线虫中，减数分裂具有在其他有性生殖系统中观察到的相同高度保守的特征。减数分裂时染色体的准确分离取决于减数分裂前期早期的标志性事件，包括同源染色体的配对、它们之间的联会以及交叉的形成。对这些过程的剖析揭示了减数分裂机制的独特简化，这影响了对更复杂系统中减数分裂染色体行为的解释。染色体配对所需的染色体位点集中在每条染色体的一端，每个染色体对的许多重组起始位点被解析为一个单一的交叉，并且沿着有丝分裂染色体长度延伸的弥散（全着丝粒）动力学活性减少到每个减数分裂染色体的一端。因此，来自线虫的研究阐明并挑战了关于同源物配对机制、交叉干扰和动粒结构的长期概念。由于染色体配对、联会和重组可以彼此独立进行，秀丽隐杆线虫为研究这些过程以及减数分裂期间介导它们协调的机制提供了一个简化的系统。本综述涵盖了秀丽隐杆线虫减数分裂的主要特征，重点是其对理解基本减数分裂过程的贡献。
