genetics part 3

Solving Punnett SquaresIf a round pea plant (AA) is crossed with a wrinkled pea plant (aa), what percent of the offspring will be:

• Round?

• Wrinkled?

If two heterozygous round pea plants are crossed, what percent of the offspring will be:

• Round?

• Wrinkled?

If a heterozygous round pea plant is crossed with a homozygous wrinkled pea plant, what percent of the offspring will be:

• Round?

• Wrinkled?

Solve these in your notebook.

Practice

• Sponge Bob Genetics

• Glue in your notebook

Solving Punnett Squares

Parents

Offspring

Predicting phenotype gets more complicated when you look at more than one trait at a time.

Solving Punnett Squares

Depending on how chromosomes independently assort determines genotype, and thus phenotype, of the resulting progeny (offspring)

Parents

Offspring

Solving Punnett Squares: page ___ of notebook

If a round, yellow pea plant (AABB) is crossed with a wrinkled, green pea plant (aabb), what percent of the offspring will be:

• Round and yellow?

• Round and green?

• Wrinkled and yellow?

• Wrinkled and green?

Practice

• Dihybrid Crosses handout (bunny rabbits). Glue in your notebook.

• Complete Dominance:

• Codominance

• Incomplete Dominance

• Sex-Linked

• Polygenic Traits

Phenotypic Expression Varies

Write this list, then we will describe each one in detail.

• Complete Dominance: Homozygous dominant genotype dominant phenotype

Heterozygous genotype dominant phenotype

Homozygous recessive genotype recessive phenotype

Phenotypic Expression Varies

Phenotypic Expression Varies

• Codominance Homozygous genotype one phenotype

Heterozygous genotype both phenotypes

Phenotypic Expression Varies

• Codominance Homozygous genotype one phenotype

Heterozygous genotype both phenotypes

Phenotypic Expression Varies

R1 R1

R2 R1R2 R1R2

R2 R1R2 R1R2

R R

W RW RW

W RW RW

• Codominance Homozygous genotype one phenotype

Heterozygous genotype both phenotypes

Practice

• Intro to blood types (first 3 minutes good)

• Complete blood typing handout and glue in your notebook.

• Incomplete Dominance Homozygous genotype one phenotype

Heterozygous genotype new phenotype

Phenotypic Expression Varies

• Incomplete Dominance Homozygous genotype one phenotype

Heterozygous genotype new phenotype

Phenotypic Expression Varies