monohybrid

An individual that is heterozygous in respect of a single gene. It is obtained by crossing parents that are homozygous for different alleles, e.g. a homozygous tall parent (TT) crossed with a homozygous short parent (tt) will produce monohybrid offspring (Tt). When selfed, a 3:1 ratio of dominant: recessive phenotypes, or some modification thereof, will be produced. This is called the monohybrid ratio. Compare dihybrid.