1. MENDEL’S LEGACY
CH. 11

2. The Father of Modern Genetics!
Gregor Mendel ( )
The Father of Modern Genetics!

3. Mendel taught natural science to High School Students.
Once: he crossed peas and mice of different varieties “for the fun of the thing”

4. He determined several “laws” of inheritance....
Mendel’s work became the foundation for Modern Genetics.

5. Mendel’s peas
MENDEL chose a common garden pea (Pisum) for his first experiments in hybridization

6. Step ONE: find plants that are “pure” for one trait (like height).
Mendel’s Procedure
Step ONE: find plants that are “pure” for one trait (like height).
Call them: P1

7. Step TWO: take opposites for the trait (like tall X short) & cross pollinate/fertilize

8. Step 3: grow offspring and record results. (F1 = filial = offspring)

9. Step 4: Allow self-pollination & grow the grandchildren of P1
Step 4: Allow self-pollination & grow the grandchildren of P1. Call this group F2. Record results.

10. P1 = HH (tall) X hh (short)
Results: All F1 grew tall!
F1 X F1 = F2
Results, 3/4th peas were tall, 1/4th peas were short!

11. Mendel discovered...
...some traits are “masked”...they are RECESSIVE and may skip generations.
...some traits are DOMINANT...they occur often in the population.

12. ...traits are determined by a pair of factors.
Alleles

13. Mendel determined...
The pair of “factors” are sorted independently of each other.
These factors are separated when the gametes are formed.

14. HOW TO PLAY GENETICS “GAMES”
Traits are expressed as letters of the alphabet.
HH or hh
Capital letters denote dominant traits

15. HH or hh are pure strains. They are called HOMOZYGOUS
Hh are mixed strains....carriers of the recessive gene, but do not look recessive. They are called HETEROZYGOUS

16. H = TALL h = short HH = homozygous tall hh = homozygous short
EXAMPLES
H = TALL
h = short
HH = homozygous tall
hh = homozygous short
Hh = heterozygous tall

17. genotype = the letters we use to express traits = genetic makeup
More vocabulary....
genotype = the letters we use to express traits = genetic makeup
phenotype = what something looks like.

18. Phenotypes
fat pod, smooth peas

19. skinny pods, wrinkled peas
or...
skinny pods, wrinkled peas