In the snail cepaea nemoralis, an autosomal allele causing a banded shell (bb) is recessive to the allele for unbanded shell (bo). genes at a different locus determine the background color of the shell; here, yellow (cy) is recessive to brown (cbw). a banded, yellow snail is crossed with a homozygous brown, unbanded snail. the f1 are then crossed with banded, yellow snails (a testcross).a. what will the results of the testcross be if the loci that control banding and color are linked with no crossing over?
b. what will the results of the testcross be if the loci assort independently?
c. what will the results of the testcross be if the loci are linked and 20 m. u. apart?