Catalyst In guinea pigs, black coat is dominant to brown coat. What would be the possible genotypes for a black guinea pig? What is the genotype for a brown guinea pig? What would be the probability of getting a homozygous black offspring from a cross between a heterozygous Black guinea pig and a brown guinea pig?

bbXBb bb B b Bb bb

Genetics Incomplete Dominance and Codominance

Complete Dominance In Mendel’s crosses one allele is always completely dominant over the other. The homozygous dominant (BB) is indistinguishable from heterozygous (Bb) in phenotype. This is called Complete Dominance

Incomplete Dominance Occurs when the phenotype of the heterozygous offspring is a blend of the two parents traits

Incomplete Dominance

What are the expected results of a cross between two pink flowers? Make a Punnett Square RW X RW

Codominance Occurs when both alleles for a gene are expressed in the heterozygous offspring. An example of codominance

Codominance Another example of codominance is Blood types in Humans. Type O, is recessive to both A and B. Types A,and B are codominant I A I A, I A iType A I B I B, I B iType B I A I B Type AB ii Type O

Codominance Lets do a problem together on the board!