1. Simple Genetics
Thursday, October 19, 2011

2. What trait shows up?
Dominant allele: capital letter; shows up no matter what.
Recessive allele: lowercase letter; shows up only when BOTH alleles are recessive.

3. Genes vs. Looks G = green allele g = yellow allele
Genotype: what alleles it has (Example: Gg, GG, or gg)
Phenotype: what it looks like (Example: Green or yellow)
G = green allele
g = yellow allele

4. Genes vs. Looks G = green allele g = yellow allele
Genotype: what alleles it has (Example: Gg, GG, or gg)
Phenotype: what it looks like (Example: Green or yellow)
What is the genotype of a yellow frog?
G = green allele
g = yellow allele

5. Genes vs. Looks G = green allele g = yellow allele
Genotype: what alleles it has (Example: Gg, GG, or gg)
Phenotype: what it looks like (Example: Green or yellow)
What is the genotype of a green frog?
G = green allele
g = yellow allele

6. Genes vs. Looks G = green allele g = yellow allele
Genotype: what alleles it has (Example: Gg, GG, or gg)
Phenotype: what it looks like (Example: Green or yellow)
What is the phenotype of a frog with the genotype Gg?
G = green allele
g = yellow allele

7. Genes vs. Looks G = green allele g = yellow allele
Genotype: what alleles it has (Example: Gg, GG, or gg)
Phenotype: what it looks like (Example: Green or yellow)
What is the phenotype of a frog with the genotype gg?
G = green allele
g = yellow allele

8. Generation to Generation
We use certain letters to represent generations
P: parents
F1: Parent’s offspring (think “children”)
F2: Offspring’s children (think “grandchildren”)

9. Punnett Square
MALE
FEMALE

10. New vocabulary Cross: to mate with
Test cross: to mate an organism with an unknown genotype with a homozygote to determine what the unknown organism’s genotype is.

11. Test Cross G = green allele g = yellow allele
Darcy found a green frog and want to determine what its genotype is. What type of frog should he mate the green frog with in order to figure out the green frog’s genotype?
Homozygous green frog
Heterozygous green frog
Homozygous yellow frog
G = green allele
g = yellow allele