Meiotic XY association could be both chiasmate and achiasmate in the Indian pygmy field mouse, Mus terricolor

摘要

Between the two alternative hypotheses explaining the nature of meiotic XY association in male mammals, chiasmate and achiasmate, only the former has gained credence. XY bivalents at diakinesis/metaphase-I in the Indian pygmy field mouse Mus terricolor make cytological visualization of chiasma feasible, due to the accretion of a block of heterochromatin distal to the pseudoautosomal region. The results revealed that meiotic XY association in M. terricolor could be either chiasmate or achiasmate, suggesting that the latter could also ensure successful meiotic progression.