Maternal effect of a hybrid inviability gene in Tribolium castaneum.

The Tribolium castaneum hybrid inviability gene, H, was selectively introgressed into a genetic background lacking H through serial paternal backcrosses. This revealed a poor viability phenotype (partial paralysis and poor control of the limbs, referred to as tremor) not present in the parent strains. Tremor cosegregated with H, but was expressed only when transmitted paternally and only when H was not also present maternally. The inferred maternal, self-suppressive effect of H may explain nonreciprocal incompatibilty previously observed between H and H-incompatible strains.