Name: Sex Determination (Drosophila melanogaster)
Uploaded: 2019-07-19
Duration: 7 min 20 s
Description: Drosophila melanogaster or the common fruit fly has contributed a lot to genetics. One of them is its sex determination system with more than five types of s...

Question

Distinguish between semi-dominant and codominant gene.

Accepted Answer

The differences between Codominant gene and Semi-dominant gene are:

Characteristics Codominant gene Semi-dominant gene

Condition In heterozygous condition, the characteristics of two codominant genes are equally expressed side by side and neither of them is recessive. In heterozygous condition, one gene is partially dominant and another gene is recessive and this dominant gene shows incomplete or partial dominance over the recessive gene.

Alleles In a heterozygote, the intermediate or mixed phenotype is not expressed, but both alleles are expressed together. In a heterozygote, a mixed or intermediate phenotype between dominant and recessive alleles is expressed.

Dominance Apparently, no dominant-recessive type of interaction between the genes is not observed. Interaction between dominant and recessive genes is observed and that results in a mixed phenotype.

Example Genes IA and IB are responsible for producing A and B blood groups respectively and in heterozygote IAIB the blood group becomes 'AB'. Red flower gene 'R' is incompletely dominant over white flower gene 'r' and in the heterozygote (Rr) the flower colour becomes pink

Distinguish between semi-dominant and codominant gene.

Important Questions on Heredity and Variation

Learn and Prepare for any exam you want !