Answer :
Answer: Recessive epistasis
Explanation:
Epistasis is a gene interaction it influences a phenotype. Genes can mask each other effect with one been dominant over the other or they can both be expressed to produce a new trait.
It is the conditional relationship between two genes that can determine a single traits. When there are two alleles that dictate phenotypes they can affect one another such that allele of one gene is recessive to one that is a dominant allele over the other.
A recessive epistasis occur when a recessive allele mask the expression of both recessive and dominant allele of another locus. Allele for white color mask the effect of other alleles expressing itself over them to give a phenotypic ratio of 9:3:4 a deviation from normal mendelian principle.
When a dominant allele masks the effect of both dominant and recessive alleles at another locus, it is a dominant epistasis.