ABSTRACT

Chromosomal rearrangements such as inversions (i.e., an orientation reversal of a piece of DNA within a single chromosome) impact species divergence by reducing recombination in heterokaryotypes (Kulathinal et al., 2009; Stevison et al., 2011). Chromosomal regions that experience reduced recombination in hybrids, such as within inversions, have been hypothesized to contribute to the maintenance of species integrity. Therefore, inversions can facilitate speciation because they are potent recombination modiers (Noor et al., 2001; Ortiz-Barrientos et al., 2002). Recombination in heterokaryotypes is severely reduced, causing associations between sets of alleles within the inversion region (Navarro and Barton, 2003). Consequently, alternative chromosomal arrangements can play a key role in speciation. In diverging populations with alternative arrangements, they may protect the inverted region from introgression and allow the accumulation of alleles that contribute to reproductive isolation (Noor et al., 2001; Reiseberg, 2001; Feder and Nosil, 2009).