Question

Unexpected ratios - epistasis

Accepted Answer

interaction of genes at diff loci, many genes interact epistatically so characteristics show continuous variation (involving many genes)
gene affected by another gene is hypostatic and gene affecting expression of another gene is epistatic
Dominant/reccessive epistasis - presence of 2 recessive alleles at epistatic gene leads to lack of protein forming (recessive epistasis), and if atleast a dominant allele present and it effects another gene its dominant epistasis (so protein formed by epistatic gene influences hypostatic gene)
Labrador colours

result of melanin, one gene codes for prod of pigment (B is black and b is brown), second gene codes for where pigment deposited (E is deposited in skin/fur and e is only on skin), gene at E locus epistatic to hypostatic gene at B locus

Gene Epistatic Epistasis Hypostatic Protein Dominant Codes Pigment