Breakpoint–chiasma interference in pericentric inversion heterokaryotypes

Heterozygous inversion breakpoints inhibit the formation of chiasmata in their vicinity, and it has been suggested that they do so through the same mechanism that also causes interference between chiasmata. In this paper, I therefore extend my earlier model of chiasma interference to account for interference between breakpoints and chiasmata in pericentric inversion heterokaryotypes. Using this model to analyze recombination and sterility datasets for Drosophila melanogaster, I find support for the hypothesis that inversion breakpoints interfere with chiasmata in the same way and to the same degree that other chiasmata do. I also find that breakpoints, like chiasmata, appear to show negative interference in the pericentromeric region, and positive interference elsewhere. I discuss the implications of these findings in light of the recent HEI10 coarsening interference hypothesis, and conclude with some remarks about the evolutionary origin of chiasma interference.