Regions in the genome cause infertility in some hybrids of house mouse subspecies
Three from one: Half a million years ago, the house mouse, Mus musculus, split into three subspecies, two of which are native to Europe. Within a transition zone, the two European forms interbreed to produce hybrids that are less fertile than their purebred kin. Two scientists at the Max Planck Institute for Evolutionary Biology in Plön have now identified sections in the genomes of such hybrid mice that reduce the animals' fertility. The genes control testicular gene activity and testicular weight. The researchers' analysis uncovered a complex web of interactions between various gene regions that can suppress reproduction between the hybrids in the course of evolution. Consequently, the mouse forms continue to diverge until the two subspecies give rise to entirely distinct species.