Question

Are dominant alleles always epistatic?
How is dominance different from epistasis?

Answer 1

Alleles is a variant form of a gene. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.
Dominance is the relationship between two alleles of the same gene. Epistasis is described as the interaction between alleles of different genes.

Complete answer:
- Dominant is a term described to the relationship between two versions of a gene.
- Individuals receive two sets of genes known as alleles from each parent.
- If the alleles of a gene are different, one allele will be expressed and it is known as the dominant gene.
- The effect of the other allele is called recessive and is neglected.
- Dominant alleles are not always epistatic because in the same genes the dominant and recessive terms are present.
- Difference between dominance and epistasis is:

Dominant	Epistasis
It is referred to as a phenomenon of genetics, in an individual that contains allelic forms of a particular gene, when expressed by exclusion of others.	It refers to a phenomenon whereby expression of one gene affects the inheritance of one or more independently inherited genes.
It is the type of interaction between alleles of different genes.	It is a type of interaction between alleles of the same genes.
Types: Codominance, incomplete dominance, complete dominance.	Types: Dominant epistasis, dominant inherited epistasis, duplicate dominant epistasis.
For example: Mendelian inheritance of the flower colour of the pea plant.	For example: Coat colour of young labrador retriever.

Note: Similarities between epistasis and dominant are,
Epistasis are the genes that always affect the same character and involve nuclear genes.
Dominant also affects the particular gene but it also involves nuclear genes.