Chapter 9: Fundamental Genetics Do Now: Construct 2 Punnett squares describing the crosses shown at left (1 for the P1 cross and 1 for the F1 cross)

Pure-breeding Plants that are pure for a trait always produce offspring with that trait. A strain is an organism that breeds pure for a certain characteristic. Mendel developed pure breeding strains for each of the 14 characteristics he studied.

Which is Haploid? Which is Diploid?

Which is Genotype? Which is Phenotype? bb

Which is Homozygous? Which is Heterozygous?

Dihybrid Crosses Construct a Punnett square to predict the outcome of a dihybrid cross between a pea plant that is heterozygous for seed color (Y = yellow, y = green) and heterozygous for seed shape (R = round, r = wrinkled) with a plant that is homozygous recessive for both traits.

Law of Segregation A pair of factors is segregated (separated) during the formation of gametes (sex cells) Y y For example: 50% Of Gametes 50% Of Gametes

Law of Independent Assortment Factors for different characteristics are distributed independently from one another. T T t t Y Y y y For example: 25% Of Gametes 25% Of Gametes 25% Of Gametes 25% Of Gametes