1. Warm Up: What is the definition of genetics? The study of heredity.
Genetics Notes Day 1
Warm Up: What is the definition of genetics?
The study of heredity.

2. Gregor Mendel (1860’s) Father of genetics. Studied pea plants.
Performed experiments with pea plants.
Used a mathematical approach.

3. Why do pea plants work well for genetic study?
Perfect flowers = male & female structures
Can do self-fertilization
Easy to grow
Produce large numbers of offspring
Can cross pollinate them
Cross pollinate: Manually take pollen from one pea plant and place it on the stigma of another pea plant.

4. Mendel’s Experiment Step 1 = Made pure breeding strains of pea plants
Let the plants self fertilize repeatedly.
Purple plants self-fertilized to make ONLY purple offspring
White plants self-fertilized to make ONLY white offspring
Collected seeds from these plants.
These were the PARENTAL GENERATION (P-Generation)

5. Mendel’s Experiment
Step 2: Mendel crossed the two varieties in the P-generation.
Purple flowers cross pollinated with white flowers.
Collected and grew the seeds from these plants
Called this the First Filial Generation (F1)
ONLY PURPLE FLOWERS GREW FROM THESE SEEDS!!!!

6. Mendel’s Experiment
Step 3: Mendel allowed the F1 generation to self-fertilize.
He collected and grew these seeds
Called this the F2 generation.
Purple flowers grew AND White flowers grew
3:1 ratio (3 purple flowers grew for every 1 white flower)

8. Mendel studied many traits of Pea Plants
Flower color (purple or white)
Seed color (yellow or green)
Seed shape (round or wrinkled)
Pod color (green or yellow)
HE ALWAYS FOUND THAT THERE WAS A 3:1 RATIO!

9. http://mac122. icu. ac. jp/gen-ed/mendel-gifs/03-mendel-characters2

10. Terms to Know Alleles: the alternative traits that are passed down
Example: mom passed down the allele for blue eyes while dad passed the allele for brown.

11. Terms Cont’d Dominant: The expressed form of the trait.
Recessive: The trait that is not expressed when the dominant allele is present.
EXAMPLE:
Allele for brown (dom) eyes from dad
Allele for blue (rec) eyes from mom
Child will have brown eyes.

12. Terms Cont’d
Homozygous: The two alleles that are passed down are the same.
Example: Both pea plant parents passed down the allele for purple flowers.
Heterozygous: The two alleles that are passed down are different.
Example: One pea plant parent passed down the allele for white flowers and one passed down the allele for purple flowers.

13. Terms Cont’d Genotype: The set of alleles that an organism has.
PP (homozygous dominant)
Pp (heterozygous)
pp (homozygous recessive)
Phenotype: The physical appearance.
purple (homozygous dominant)
purple (heterozygous)
white (homozygous recessive)