'Selfish driver' genes make you sick if you have only one copy; this limits hybrids. "Nuckolls et al. created fluorescent versions of the poison and the antidote and mapped their location inside and around the gametes. These elegant experiments showed that wtf4’s poison can leave their originating cells and cross into surrounding cells while the antidote remains trapped inside the cells that produce it."
Best gene name ever ("wtf"). And very descriptive.