In wheat, kernel color is determined by additive alleles at two unlinked loci.If two plants, with red kernels, heterozygous at both loci, are crossed, what fraction of the offspring is expected to have phenotypes distinct from parental?
A)1/16
B)4/16
C)6/16
D)10/16
E)All the offspring will have parental phenotypes.

Question

Quizplus · Accepted Answer

In a dihybrid cross where both parents are heterozygous at two loci (AaBb x AaBb), the offspring can have a variety of genotypes. The phenotypes distinct from the parental phenotype occur when the offspring inherit either recessive alleles at both loci (aabb) or a combination that does not resemble the parent's dominant phenotype (e.g., AAbb, aaBB, Aabb, aaBb, AaBb). Using a Punnett square, you can calculate that 6/16 will have the same phenotype as the parents (A-B-), and 10/16 will have phenotypes distinct from the parents, including the fully recessive phenotype (aabb) and combinations thereof.

In Wheat, Kernel Color Is Determined by Additive Alleles at Two