Question

what is the genotypic and phenotypic ratio of f2 generation in codominance
please explain....

Answer 1

the F2 progeny will consist of three distinct phenotypes with a ratio that is identical to the genotypic ratio, that is, 1:2:1.

Explanation:

This is a type of dominance in which the heterozygote exhibits a phenotype that reflects both characters carried by the two alleles making up the heterozygous genotype. In this case both alleles are equally dominant and are thus visible in the heterozygote.

As to our hypothetical cross between parents possessing homozygous genotypes (p1p1 and p2p2), it is the dominance relation in which the heterozygote (p1p2) exhibits both paternal characters. The heterozygote (p1p2) will thus have pods each of which may be colored with patches, spots, or mosaic of green and yellow.

Therefore, the F2 progeny will consist of three distinct phenotypes with a ratio that is identical to the genotypic ratio, that is, 1:2:1. Likewise, codominance forms a new phenotype in the heterozygote that is distinct from either parental types.

The following expected observations will further illustrate the concept of this intraallelic interaction:

• F1 genotype: p1p2

• F1 phenotype: pods with patches, spots, or mosaic of green and yellow

• F2 genotypes and ratio: 1:2:1 (1p1p1:2p1p2:1p2p2)

• F2 phenotypes and ratio: 1:2:1 green, green and yellow, and yellow (1p1p1:2p1p2:1p2p2)