You are trying to find genes that affect fruit size in straw

You are trying to find genes that affect fruit size in strawberries. You cross a small and large fruited individual, and then backcross to the large fruit parent type. You then phenotyped and genotyped backcross offspring. You notice that individuals that are heterozygous at a particular marker (A) have a variety of fruit sizes ranging from medium to large. What can you conclude from this result?

A: The mutant gene is tightly linked to marker A

B: The mutant gene is not tightly linked to marker A

C: Marker A is sompletely dominant

D: There is epistasis between Marker A and a gene affecting fruit size.

I know that the answer is B, but why?

Solution

As the A is linked to varity sizes of fruit from medium to large the it can be conclude that mutant gene is tightly linked to marker A