Novitski’s Distal shift in Paracentric Inversion Evolution

In Drosophila pseudoobscura younger chromosomal inversions tend to be found distal to older inversions. By examining phylogenetic series of overlapping inversions for 134 gene arrangements of 13 chromosomes this pattern was extended to five additional Drosophila species. This distinct pattern arose repeatedly and independently in all six species and likely reflects an underlying principle of chromosome evolution. In this study it is illustrated how transmission of distal inversions is always favored in female meiosis when crossing over in homosequential regions of overlapping inversions generates asymmetric dyads. This cytogenetic mechanism for female meiotic drive is described in detail and advanced as an explanation for the distal shift in phylogenetic series of overlapping inversions as well as several better known patterns in the evolution of serially inverted chromosomes.