Analysis of meiosis in < i > Pristionchus pacificus < /i > reveals plasticity in homolog pairing and synapsis in the nematode lineage

Meiosis is conserved across eukaryotes yet varies in the details of its execution. Here we describe a new comparative model system for molecular analysis of meiosis, the nematodePristionchus pacificus, a distant relative of the widely studied model organismCaenorhabditis elegans.P. pacificus shares many anatomical and other features that facilitate analysis of meiosis inC. elegans. However, whileC. elegans has lost the meiosis-specific recombinase Dmc1 and evolved a recombination-independent mechanism to synapse its chromosomes,P. pacificus expresses both DMC-1 and RAD-51. We find that SPO-11 and DMC-1 are required for stable homolog pairing, synapsis, and crossover formation, while RAD-51 is dispensable for these key meiotic processes. RAD-51 and DMC-1 localize sequentially to chromosomes during meiotic prophase and show nonoverlapping functions. We also present a new genetic map forP. pacificus that reveals a crossover landscape very similar to that ofC. elegans, despite marked divergence in the regulation of synapsis and crossing-over between these lineages.
Source: eLife - Category: Biomedical Science Tags: Cell Biology Genetics and Genomics Source Type: research