Question

17.(5 points) black (b) is dominant to brown (b) color in labrador retrievers. there is a second gene that controls pigment placement (c), but if there are two recessive copies of the gene, no pigment is placed (c). what type of genetic phenomena has been described?

Answer 1

The genetic phenomena described, where black color (B) in Labrador retrievers can be overridden by the epistatic gene that controls pigment placement (c), is known as epistasis.

Step-by-step explanation:

The genetic phenomena being described in Labrador retrievers regarding the dominance of black color to brown, along with a second gene that controls pigment placement, is known as epistasis. Epistasis occurs when one gene's effect is modified by another gene. In the example provided, the 'c' gene controls whether pigment is expressed at all, so even if a Labrador has the genotype for black coat color ('B'), if it possesses two recessive alleles at the second locus ('cc'), it will not produce any pigment, effectively hiding the expression of the 'B' gene. This interaction shows how the 'c' gene is epistatic to the 'B' gene, because its expression can override the potential effects of the 'B' gene with regards to coat color.