Epistasis and Dominance: Similarities and Dissimilarities

In this article we will discuss about the Similarities and Dissimilarities between Epistasis and Dominance.

Similarities between Epistasis and Dominance:

Epistasis:

1. Epistasis genes always affect the same character.

2. Epistasis involves nuclear genes.

Dominance:

1. Dominant gene also affects a particular character.

2. Dominance also involves nuclear genes.

Dissimilarities between Epistasis and Dominance:

Epistasis:

1. Epistasis refers to interaction of two or more genes. Thus it involves two or more loci.

2. Epistasis may involve both homo and heterozygotes. Hence it is fixable in homozygotes.

3. Epistasis is of several types such as dominant, recessive, duplicate, etc.

4. Epistasis modifies the normal dihybrid phenotypic ratios in F₂.

5. Epistasis is also known as inter genie or inter-locus gene interaction.

6. Recessive gene can also exhibit masking effect.

Dominance:

1. Dominance refers to the interaction of two alleles of the same gene. Thus it involves single locus.

2. Dominancealways refers to heterozygotes and, therefore, it is not fixable

3. Dominance is of three types, i.e., incomplete, complete and over dominance.

4. Partial dominance alters the normal segregation ratio of 3 : 1 into 1:2:1.

5. Dominance is known as intragenic or intra-locus gene interaction.

6. Recessive gene can express only in homozygous condition.