1. Mendel & Genetics

2. Genetics Genetics is the study of heredity.
Heredity is the passing of a physical trait from parent to offspring.
Traits are different forms of characteristics ex. eye color, hair color

3. Gregor Mendel Wondered why pea plants are
different- tall, short, green seed,
yellow seed, etc.
He cross-pollinated pea plants (took pollen from 1 plant to another) in order to see how traits were passed on
Considered the Father of Genetics

4. Mendel Continued
Mendel figured out that traits are carried in pairs on structures called chromosomes.
Chromosomes are made up of DNA and have specific sections called genes.

5. Mendel’s Experiments Purebred (homozygous)- an offspring with
the same exact traits ex. a purebred short pea plant would have short parent plants
Hybrid (heterozygous)- offspring has two different forms of a trait ex. a hybrid tall pea plant could have a short and
tall parent

6. Generations P Generation- Parent generation
F1- Offspring of the P generation
F2- Offspring of the F1 generation

7. Genes & Alleles
Gene- a factor that controls a trait. You get one from each parent.
Alleles- Different forms of a gene Ex. one allele for short, one allele for tall
** Traits are controlled by the alleles inherited from parents**

8. Forms of Alleles Dominant: trait will ALWAYS show up when present
represented by a capital letter ( AA = 2 dominant alleles)
Recessive:
trait is HIDDEN when there’s a dominant allele
represented by a lowercase letter (Aa= 1 dominant, 1 recessive so recessive DOES NOT show up)

9. T= brown hair t= red hair
PRACTICE!
T= brown hair t= red hair
Tt:
TT:
tt:
G= short g= tall
GG:
gg:
Gg:

10. Practice! Label as hybrids or purebreds: Tt: TT: tt: 4. GG: 5. gg:

11. Phenotype & Genotype
Phenotype: An organism’s physical appearance like widow’s peak or attached earlobes.
Genotype: An organism’s genetic make up like the allele combinate (tt or Tt or TT)

12. Phenotype/Genotype Practice
T= brown hair t= red hair
Tt:
TT:
tt:
G= short g= tall
Homozygous short:
Heterozygous short:
Purebred tall:

13. Punnett Squares
This is a table that shows the probability of an individual getting a trait.

14. Punnett Square
Step 1: Put the parent’s alleles on the side and top of the table.

15. Punnett Square
Step 2: Drop the top letters down. Bring the side letters across.

16. Practice!
B= Tongue roller T= Dimple
b= Can’t roll tongue t= No dimple

17. Practice! 1st Punnett Square: 2nd Punnett Square:
What percentage of What percentage of
Offspring will not be offspring will have
Able to roll their dimples?
tongue?

18. Sources