1. Genetics
Chapter 6 & 7

2. Gregor Mendel
Austrian Monk who tended plants at a monastery in 1865

3. Gregor Mendel
By experimenting with pea plants he was the first to correctly identify patterns of inheritance.

4. Gregor Mendel
The methods he used forms the basis of our modern genetics.
Known as the “Father of Genetics”

5. Mendel’s Experiment

6. A pure strain is a group that always exhibit the same trait.
Crossing Pure Strains
A pure strain is a group that always exhibit the same trait.

7. An example is a group of pea plants that are always tall.
Crossing Pure Strains
An example is a group of pea plants that are always tall.

8. Mendel called his pure strains the P1 generation (parents).
Crossing Pure Strains
Mendel called his pure strains the P1 generation (parents).

9. He pollinated a pure tall plant with a pure short plant
Crossing Pure Strains
He pollinated a pure tall plant with a pure short plant

10. All the offspring were tall!!! He called them the F1 Generation

11. Crossing Pure Strains
The offspring are the F1 Generation
If all of the F1’s were tall
Then the short trait seemed to disappear

12. Crossing Pure Strains This happened with every cross that he did.
Green X Yellow = All green
Round X Wrinkled = All round

13. He called the trait that showed up dominant.
Crossing Pure Strains
He called the trait that showed up dominant.

14. The trait that disappeared was called recessive.
Crossing Pure Strains
The trait that disappeared was called recessive.

15. Cross of F1’s
Next Mendel crossed two of the F1 tall plants.

16. Cross of F1’s
Out of all offspring, 75% were tall and 25% were short. This happened with every trait (green,yellow, round, wrinkled)

17. F2 Generation

18. As a result of the pea plant experiments Mendel learned that:
1. One factor may mask another. The dominant factor may mask the recessive factor.
The dominant is represented by a capital letter (T). Recessive is lowercase (t).

19. Mendel also learned that
2. Every offspring has 2 factors that make up a trait. One coming from each parent. These factors are called alleles.

20. Mendel’s Laws

21. Law of Segregation
A parent passed on at random only 1 allele for each trait to each offspring.

22. Law of Segregation
Example: A mother’s egg can only carry a T for tall or a t for short. Even though her genotype is Tt.

23. Law of Independent Assortment
Genes for different traits are inherited independently of each other.

24. Law of Independent Assortment
Example: Plant height and seed color are not linked.

25. Punnett Squares
An English biologist named Punnett came up with a short hand way of finding proportions: the Punnett Square

26. A monohybrid cross involves 1 trait.
Punnett Squares
A monohybrid cross involves 1 trait.
Example: Gg x gg (pea plant color)

27. Punnett Squares
A dihybrid cross involves 2 traits.
Ex: TTGG x ttgg (pea height and color)

28. Punnett Squares
A homozygous (purebred) individual has 2 alleles that are the same.
Example: TT, tt

29. Punnett Squares Homozygous Dominant = TT (pure strain tall)
Homozygous Recessive = tt (pure strain short)

30. Punnett Squares
A heterozygous (hybrid) individual has 2 alleles that are different.
Example: Tt (hybrid tall)

31. Punnett Squares
The way an organism physically looks is it’s phenotype.
The gene combinations an organism contains is it’s genotype.

32. Punnett Squares
Example of phenotype: brown eyes
Example of genotype: Bb

33. Genetic Traits and Disorders

34. Polydactyly

35. Hitchhiker’s Thumb

36. Widow’s Peak

37. XYY Syndrome

38. Sickle-Cell Anemia

39. Polygenic Eye Color

40. The End