How Can Satellite DNA Divergence Cause Reproductive Isolation? Let Us Count the Chromosomal Ways
Figure 3
Segregation distortion in hybrid animals. (a) Postmeiotic release of segregation distortion in hybrid males. A recessive suppressor of distortion (su) in one species becomes inactive in the heterozygous hybrid. This allows the distorting locus to target a satellite block on the chromosomes of the other species (top). This effect results in spermatid bundles (bottom) in which spermatids inheriting the targeted chromosome fail to individualize. The spermatids carrying the chromosome with the distorting locus develop normally. (b) Release of meiotic drive in hybrid females. A recessive suppressor becomes heterozygous in the hybrid female. This enables a chromosome from one species, which carries a “selfish” satellite, to outcompete the homologous chromosome from the other species. As a result, the egg nucleus will carry a chromosome with the selfish satellite, and chromosomes lacking these satellites will end up in the unused polar bodies.
