Genetic Crosses

Genotype vs Phenotype

Homozygous vs Heterozygous

Monohybrid Crosses Monohybrid Cross: a cross that only one characteristic is tracked is monohybrid. Punnett Square: a diagram used to aid biologists in predicting the probable distribution of inherited traits in offspring. Six Examples: .

Example One: Homozygous X Homozygous

Example Two: Homozygous X Heterozygous

Example Three: Heterozygous X Heterozygous

Example Four: Testcross How can you determine if a guinea pig is homozygous (BB) or heterozygous (Bb)?

Example Five: Incomplete Dominance

Example Six: Codominance

Dihybrid Cross Dihybrid cross: is a cross which two characteristics (genes) are tracked. The offspring of the animal being crossed in a dihybrid cross is called a dihybrid. Two examples: .

Example One: homozygous X homozygous Two seeds with two different genes being expressed: (1) wrinkled, green (rryy) (1) round, yellow seed (RRYY)

Example Two: Heterozygous X Heterozygous Use the same procedure as in homozygous x homozygous.