1. 11-3 Exploring Mendelian Genetics

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

3. Phenotype: yellow, round
C. Parental cross: True- breeding yellow and round seeded pea plant x true-breeding green and wrinkled seeded pea plant.
P _____ X _____
F₁ ______
All offspring were:
Genotype: heterozygous yellow heterozygous round.
Phenotype: yellow, round
YYRR
yyrr
YyRr

4. YyRr D. Then Mendel crossed two F₁ offspring.
F₁ _________ X_____________
YyRr
YyRr
YyRr

5. 9:3:3:1 phenotype ratio The ratio found when crossing
2 heterozygotes for 2 traits
(dihybrid) was a
9:3:3:1 phenotype ratio

6. From this, Mendel concluded (4th 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, which can be good for survival of a species!

7. What is the Ratio for crossing a homozygous-homozygous with a heterozygous-heterozygous?
1:1:1:1