2. Genetics
The study of genes, variation and heredity in living organisms.
Genetics is a study linking biology, mathematics, & biochemistry.

3. Basic vocabulary needed for studying genetics:
Okay, before we begin.
Basic vocabulary needed for studying genetics:
Gene
Trait/Characteristic
Allele
Dominant
Recessive
Heterozygous
Hybrid
Homozygous
True-breeding
Genotype
Phenotype
Axial Flowers
Petal Color
Axial AA
White pp
Height Tt
Tall
Pea Pod Color
Green Gg
DNA Strand

4. History of Genetics 1822-1884 Father of Genetics
Identified the rules of heredity
Saw that living things pass traits to the next generation.
Observed traits skipping generations

5. Mendel’s Experiments
Around 1854, Mendel chose to use peas for his experiments.
He cross-fertilized pea plants that had clearly opposite characteristics
Tall/Short
Yellow/Green

6. Pea Plant Opposite Characteristics

7. Mendel’s Experimental Design
First: Mendel crossed a “pure” white flowered plant with a “pure” purple flowered plant
Second: a cross was done of the seeds resulting from the first cross
Third: Mendel observed that the trait for white flower color skipped a generation

8. Mendel wanted to know why traits seemed to skip generations.
His work to answer that question resulted in the first laws of genetics and a rule:
Rules of Dominance
The Law of Segregation
The Law of Independent Assortment

9. What Mendel discovered.
The Rules of Dominance
One trait masks or hides another trait.
If a dominant allele is present then the so called recessive allele is masked.
If simply dominant, then the heterozygous and homozygous genotype will reflect dominant phenotype.
Example:

10. The Law of Segregation
This law states that allele pairs separate/ segregate during gamete formation (meiosis), and randomly unite at fertilization.

11. The Law of Independent Assortment
This law states that when two or more characteristics are inherited that the combinations of traits in the offspring do not always match the combination of traits in the parent organisms.
Blonde - Blue
Blonde - Brown
Blonde - Green

12. Patterns of Inheritance

13. Pattern of Inheritance (POI) 1
Genetics
Punnett’s Square
Pattern of Inheritance (POI) 1
Simple Dominance

14. Punnett’s Square Four potential offspring.
Reginald Punnett & William Bateson (1905)
A matrix that shows how gametes (sex cells) combine to make zygotes (fertilized eggs).
One Sperm Cell
One Egg Cell
Four potential
offspring.

15. POI: Simple Dominance
The first type of Punnett’s Square Problem we are going to learn about is called Simple Dominance.
The rules for this POI are:
One allele is dominant
One allele is recessive
When heterozygous (mixed), the alleles show the dominant phenotype.

16. Practice Problem #1
In pea plants, purple flower color is dominant to white flower color. A purple flowered plant is crossed with another purple flowered plant and some of the offspring are white.
Determine the genotypes of the parent plants.
Determine what percent of the offspring could be white.

17. Practice Problem #2
Albinism in humans is inherited as a simple recessive trait. For the following families, determine the genotypes of the parents and offspring.
Two non-albino parents have four children, three normal and one albino.
A normal male and an albino female have six children, all normal.

18. Practice Problem #3
In humans, brown eyes are dominant to blue. If a man with blue eyes has a child with a woman with brown eyes (but her mother had blue eyes).
What is the percent chance of them having a child with brown eyes?
What is the percent chance of them having a child with blue eyes?

19. Now, you create a practice problem.

20. TedTalk

21. Dihybrid Crosses
Crossing a woman who is heterozygous for brown hair and recessive for blue eye color with a man who is homozygous for blonde hair and homozygous dominant for brown eyes.