11-3 Exploring Mendelian Genetics

I. Independent Assortment A.Mendel wondered if the segregation(separation) of one pair of alleles (which make up one gene) affected the segregation of another pair of alleles B.He did experiments where he followed two different genes. Ex. Color and shape of pea plant seeds

C. Parental cross: True- breeding yellow and round seeded pea plant x true-breeding green and wrinkled seeded pea plant. P _____ X _____ F ₁ ______ All offspring were: Genotype: heterozygous yellow heterozygous round. Phenotype: yellow, round YyRr YYRR yyrr

D. Then Mendel crossed two F ₁ offspring. F ₁ _________ X_____________ YyRr

E.The ratio found when crossing 2 heterozygotes for 2 traits (dihybrid) was a 9:3:3:1 phenotype ratio

F.From this, Mendel concluded (4 th conclusion from all his experiments): 1. The principle of independent assortment- states that alleles, for different genes, can segregate independently during gamete formation. 2. This allows for variations in organisms.