Epigenetically mismatched parental centromeres trigger genome elimination in hybrids
Mohan P A Marimuthu, Maruthachalam Ravi, Ramesh Bondada, Sundaram Kuppu, Ek Han Tan, Anne Britt, Wan Chan, Luca Comai
Abstract
eggs and early zygotes, while wild-type CENH3 persists. In the hybrid zygotes and embryos, CENH3 and essential centromere proteins load preferentially on the CENH3-rich centromeres of the wild-type parent, while CENH3-depleted centromeres fail to reconstitute new CENH3-chromatin and the kinetochore and are frequently lost. Genome elimination is opposed by E3 ubiquitin ligase VIM1. We propose a model based on cooperative binding of CENH3 to chromatin to explain the differential CENH3 loading rates. Thus, parental CENH3 polymorphisms result in epigenetically distinct centromeres that instantiate a strong mating barrier and produce haploids.