Dihybrid Crosses and Co-dominance

Dihybrid Crosses

When 2 characteristics are inherited from 3 different genes which have different alleles.These can show the probability of inheriting certain combinations of 2 different characteristics from their parents.

Genetic diagrams

An allele from one chromosome can enter a gamete with either allele rom the other pair because of independent segregation so possible genotypes of gametes from an AaBb adult: AB, Ab, aB, ab

Co-dominant

Alleles which both contribute to the phenotype (ie. produce a blended effect) in the heterozygous condition.

Co-dominance

Alleles can be co-dominant if they are both expressed in the phenotype as neither one is recessive.

It can mean that both appear in the phenotype, or they can make a blend.