Incomplete Dominance

1. Incomplete Dominance • Inheritance in which an active allele does not entirely compensate for an inactive allele • The result is an offspring that is an intermediate between the two phenotypes (not a blending, an intermediate)

2. Codominance • Condition in which both alleles of a gene are completely expressed

3. Multiple Alleles • When three or more alleles of the same gene code for a single trait • Ex: Fur color in mice • 2 genes: one codes for black or brown color, the other codes for color presence • B is black and b is brown • C is for color presence and c is for no color

4. Pedigrees • Shape refers to gender • Boxes signify “male” • Circles signify “female” • Fill representsdegree of affect • Filled in box/circle means “affected” • Half-filled in box/circle means “carrier” • Empty box/circle means “unaffected”

5. Dihydrid practice In rabbits, the coat color black dominant (B) over brown (b). Short hair is dominant (S) over long (s). In a cross between a heterozygous black, heterozygous short-haired male and a brown, long-haired female, what would be the phenotypic ratio of the F1 generation?

6. A sexually reproducing animal has two unlinked genes, one for head shape (H), and one of tail length (T). Its genotype is HhTt. Identify the possible genotypes of the gametes that could form from this organism?

7. What is the genotype of individual B5? • What is the likelihood that the offspring of D3 and D4 will have wooly hair? • What is the probability that C1 has the genotype Ww?

8. Three babies were mixed up at the hospital. After considering the data table below, which of the following represents the correct baby and parent combinations?