Protein phosphatase 2A protects centromeric sister chromatid cohesion during meiosis I

Segregation of homologous maternal and paternal centromeres to opposite poles during meiosis I depends on post-replicative crossing over between homologous non-sister chromatids, which creates chiasmata and therefore bivalent chromosomes减数分裂I（meiosis I）期间，同源母源与父源着丝粒（centromere）分离至细胞两极的过程，依赖于同源非姐妹染色单体间的复制后交叉互换；这一交叉互换过程会形成交叉（chiasmata），进而构成二价染色体（bivalent chromosomes）。