PATHOLOGY

Detailed explanation-1: -Short tails (T) are dominant to long tails (t). What fraction of the progeny created by crossing BbTt × BBtt will be expected to have black fur and long tails? 1/16.

Detailed explanation-2: -In mice, black fur (B) is dominant to brown fur (b) and a short tail (T) is dominant to a long tail (t). Two mice with the genotype BbTt have two separate litters of offspring together.

Detailed explanation-3: -The recessive gene in the black mice is in codominant and incomplete dominance with the white allele. However, the black mice have different recessive genes. We believe that these genes are white and brown. Because the black mice have a recessive white gene, we believe black is dominant over white.

Detailed explanation-4: -The black and brown colors do not blend together: the black allele covers up the brown allele. This means that the black allele is dominant over the brown allele. Remember that dominant alleles cover up recessive alleles. If there is one dominant allele present, the dog will appear black.

Detailed explanation-5: -The allele for black fur (FB) is co-dominant with white fur (FW) in mice and when both the alleles are present together, the mice will have black and white spotted fur. The allele for brown eyes (B) is dominant over blue eyes (b) in mice.