1. Mendel’s Laws of Heredity
Gregor Mendel ( )– Conducted experiments with pea plants and laid the foundation for the study of genetics
Mendel’s Laws of Heredity

2. endel Genetics – Scientific study of heredity What is heredity?
What are traits?

3. Peas are self-pollinating
Mendel
Peas are self-pollinating
Pollination
Fertilization
Gametes
Zygote

4. 11.1 Mendel
Why is self pollination a problem?

5. 11.1
Notice the parental generation is the P generation
WHAT WAS THE OUTCOME???

6. ALL YELLOW Mendel Why did the other parent’s trait disappear??
Notice that this is the F1 generation, the first filial generation
ALL YELLOW

7. Mendel
Mendel's first conclusion was that inheritance is determined by factors passed from one generation to the next. These factors are….
Genes
Alleles

8. Mendel
Mendel’s second conclusion was that some of these alleles are dominate
Principle of dominance.

9. Mendel
Did the recessive alleles disappear or were they still present in the F1 generation???

11. Mendel
What did Mendel conclude from this? The Law of Segregation

12. Mendel

13. Mendel
Genotype
Phenotype

14. Punnett Squares Monohybrid cross
Now we need to segregate their alleles
Now we can cross our alleles
First we need parents
Anything with a dominate allele displays the dominate trait
Now we need to give them genotypes Tt Tt t tt Tt Tt t

15. 11.2 Punnett Squares
Homozygous
Heterozygous

16. Like monohybrid crosses except with two traits.
Dihybrid Crosses
Like monohybrid crosses except with two traits.
We could predict a cross between two pea plants that are both heterozygous for yellow color and smooth seeds (opposite would be wrinkled).
What are their genotypes?
RrYy and RrYy

17. Dihybrid Cross
To find the gametes for the outside of the punnet square you can use FOIL: (Rr)(Yy)
First – RY
Outside – Ry
Inside – rY
Last – ry

18. RY Ry rY ry
RRYY
RRYy RY Ry rY ry

19. Independent Assortment
The results from this cross show that the alleles for seed shape segregate independently from alleles for seed color.
One gene does not effect the inheritance of another gene
During the formation of gametes genes for different traits segregate independently