The term 'meiotic drive' refers to any process which causes some alleles to be over-represented in the gametes which are formed during meiosis.

With normal Mendelian segregation at a genetic locus, on average half of an organism's offspring inherit one of the alleles and the other half the other allele. There are, however, some curious cases in which Mendel's laws are broken, and one of the alleles is consistently found in more than half the offspring.

The segregation distorter gene of Drosophila melanogaster (opposite) is an example.