1. LEQ: How do genes assort independently? 9.4 to 9.6

2. Homologous Chromosomes Each chromosome of a homologous pair carries a copy for the same gene. Each chromosome of a homologous pair carries a copy for the same gene. For most genes there are two alleles. What would be the exception? For most genes there are two alleles. What would be the exception? Traits on sex chromosomes. Traits on sex chromosomes. The alleles can be the same The alleles can be the same Homozygous Homozygous The alleles can be different The alleles can be different Heterozygous Heterozygous

3. Dihybrid Cross Genetic Cross of individuals differing in 2 traits Genetic Cross of individuals differing in 2 traits 16 boxes 16 boxes Determine possible gametes Determine possible gametes A with P, A with p, a with P and a with P A with P, A with p, a with P and a with P Keep alleles together (A with A and P with P) Keep alleles together (A with A and P with P) Capitol letter before lowercase Capitol letter before lowercase

4. Independent Assortment

5. When Mendel conducted dihybrid crosses he noticed new gene combinations (different from the P and F1) When Mendel conducted dihybrid crosses he noticed new gene combinations (different from the P and F1) From that he came up with the Law of Independent Assortment: From that he came up with the Law of Independent Assortment: Each pair of alleles segregates independently from other pairs of alleles during gamete formation Each pair of alleles segregates independently from other pairs of alleles during gamete formation The genes did not have to be inherited together The genes did not have to be inherited together

6. Independent Assortment When do genes independently assort? When do genes independently assort? Metaphase 1 of Meiosis Metaphase 1 of Meiosis

7. Test Cross A cross between an individual of unknown (homozygous dominant or heterozygous) genotype and a homozygous recessive individual A cross between an individual of unknown (homozygous dominant or heterozygous) genotype and a homozygous recessive individual If any offspring are recessive, then… If any offspring are recessive, then… Unknown is heterzygous Unknown is heterzygous If all offspring are dominant, then… If all offspring are dominant, then… Unknown is homozygous Unknown is homozygous