Japanese Bantam - Genetics

Genetics

One unusual characteristic of Japanese bantams is extremely short legs. The trait is mainly caused by a single lethal gene, and all Japanese bantams are heterozygous. When the bantams are bred, 25% of the embryos receive two mutant alleles and die before hatching. 50% of the embryos receive one mutant allele and one wild type allele and are short-legged. The remaining 25% receive two wild type alleles and have legs that are longer than what most breeders want. When the long-legged birds are bred together, they never produce offspring with short legs.