Data for "Hybrid female infertility due to cohesin protection errors".

Microscopy images in the Figures and Supplemental Figures in Totsuka et al "Hybrid female infertility due to cohesin protection errors".AbstractHybrid incompatibility can lead to lethality and sterility of F1 hybrids, facilitating speciation. Cell biological basis underlying hybrid incompatibility remains largely unknown, especially in mammals. Here we found that female hybrids between Mus musculus and Mus spicilegus mice are sterile due to the failure of homologous-chromosome separation in oocyte meiosis, producing aneuploid eggs. This nondisjunction phenotype was driven by the mis-localization of the cohesin-protector, SGO2, along chromosome arms instead of its typical centromeric enrichment, resulting in cohesin over-protection. The upstream kinase, BUB1, showed a higher activity in hybrid oocytes, explaining SGO2 mis-targeting. Higher BUB1 activity was not observed in mitosis, consistent with viable hybrid mice. Cohesion defects were also evident in hybrid mice from another genus, Peromyscus, wherein cohesin protection is weakened. Defective cohesion in oocytes is a leading cause of reduced fertility. Our work provides evidence that a major cause of human infertility may play a positive role in mammalian speciation.