Epistasis was first studied by ___________.
The masking of the phenotypic effect of alleles at one gene by alleles of another gene. A gene is said to be epistatic when its presence suppresses the effect of a gene at another locus. Epistatic genes are sometimes called inhibiting genes because of their effect on other genes which are described as hypostatic. This was first studied by Morgan.
So, the correct option is ‘Morgan’.