Gene Interaction Experiment by Bateson and Punnett - A classical example of gene interaction based on the results of cross between different breeds of chicken was reported. In the early part of the 20th century, W. Bateson and R.C. Punnett crossed domestic breeds of chickens such as Wyandottes, brahmas, leghorns, etc., having different types of combs. Wyandottes have a characteristic type of comb called rose whereas brahmas have a pea comb and leghorns have a single comb.

When a cross is done between Wyandottes and Brahmas, all F I chicken had combs with a phenotype not expressed in either parent. When the F I chicken were mated among themselves and large F 2 population were produced, a familiar dihybrid ratio 9: 3: 3: 1 was recognized but the phenotype representing two of the four classes were different from those expressed in the parents. About 9/16 of the F2 birds were walnut, 3/16 were rose, 3/16 were pea and 1/16 had single combs.

1.The offspring obtained from a cross of Wyandottes and Brahmas showed a comb of walnut type, a characteristic which none of the parents have.

2. Two phenotypes (walnut and single) not expressed in the original appeared in F 2.

The genes Rand P were non allelic but each was a dominant over its allele. When Rand P were together, as in the F 1 (RrPp), the two different products interacted to produce a walnut comb. The two non allelic genes Rand P acted independently in different ways similar to the ways in which dominant alleles act.