1. Alleles segregate during gamete formation, but do they do it independently?

2. Two-factor Cross, F 1 RRYY x rryy Round/yellow peas wrinkled/green What will offspring look like? Gives hybrid plants needed for next cross

3. Two-Factor Cross, F 2 RrYy x RrYy

4. Independent Assortment Genes for different traits can segregate independently during the formation of gametes. Leads to genetic variation in plants, animals, and other organisms.

5. Not all genes show simple patterns of dominant and recessive Incomplete dominance Codominance Multiple alleles Polygenic traits Sex-linked

6. Incomplete Dominance One allele NOT dominant over another Four o’clock plants RR x WW RW

7. Codominance Both alleles contribute to the phenotype Chicken: black feathers codom with white Heterozygous = erminette (speckled) Humans: protein controlling cholesterol levels Blood type

8. Multiple Alleles Many genes have more than 2 alleles Coat color in rabbits Human gene for blood type

12. Polygenic Traits Traits controlled by two or more genes At least three genes involved in reddish- brown pigment in eyes of fruit flies Different combinations of alleles produce different eye colors Polygenic traits often show a wide range of phenotypes Skin color in humans partly because more than four different genes probably control this trait

13. Sex-linked Genes