1. Pea In Your Genes

2. Gregor Mendel Liked to play with pea Father of Genetics
Noted passing of traits from parents to offspring – heredity
Study of heredity - Genetics
plants.

3. A single trait can be expressed (shown) in different ways.
Allele is the different representation of the same trait. Ex. Seed color: Yellow or Green
Yellow is one Allele for Seed Color
Green is another Allele

4. Genotype & Phenotype
Genotype – “code” for a trait. Letters we use. Ex. Yy
Phenotype – what you actually see.
Yellow peas – Use Y to represent Yellow
Green peas – Use y to represent Green

5. Yellow and Green Peas Genotype Phenotype
YY – Yellow – Homozygous Dominant
Yy – Yellow - Heterozygous
yy – Green –Homozygous Recessive
The ONLY way a recessive trait is EVER seen is if the GENOTYPE is Homozygous Recessive – or yy.

6. Three different Genotypes but Two Colors. Why?
YY – Yellow
Yy – Yellow
yy - Green
Dominant Allele – rep. by a capital letter – Y
Recessive Allele – rep. by a lowercase letter - y
Dominant Alleles OVER POWER Recessive Alleles

7. YY – Homozygous Yellow
Yy – Heterozygous Yellow
yy – Homozygous Green

8. Complete Dominance
Dominant Allele completely masks recessive allele.

9. Incomplete Dominance
Incomplete dominance = one allele is not completely dominant over the other.

10. Codominance
Codominance= condition in which both alleles for a gene are expressed when present

11. What to know: Mitosis Cells begin and end 2N
Be able to know, draw, and recognize EACH step.
Know what the “Big Event” of each step is. Ex. Metaphase – line up middle

12. Cross-Over
Increases Genetic Variety

13. What to know: Meiosis Prophase I – ONLY stage where Cross-Over occurs
Meiosis begins 2N and ends 1N
Be able to know, draw, recognize EACH stage of Meiosis.
Know what the “Big Event” of each step is.

14. How do alleles pass from parent to child?y y
Punnett Squares
What if you cross a Homozygous Yellow Pea (YY) with a Homozygous Green Pea (yy)? y y Y Y Y y y Y Y Y
100% Heterozygous Yellow Peas

15. Y y y Y Y Y Y y y y y Y 25% Homozygous Yellow 50% Heterozygous Yellow
25% Homozygous Green
Genotype Ratio: 1:2:1 y Y Y Y Y y y y y Y

16. Incomplete and Complete Dominance

17. Complete Dominance
Dominant Allele completely masks recessive allele.

18. Incomplete Dominance
Incomplete dominance = one allele is not completely dominant over the other.

19. Codominance
Codominance= condition in which both alleles for a gene are expressed when present

20. Dihybrid Cross Start with FOIL
Put results of FOIL for parent one at top
Put results of FOIL for parent two to the left
Distribute like monohybrid cross.

21. FOIL
First
Outside
Inside
Last
RrSs RS Rs rS rs

22. RrSs x RrSs RS Rs rS rs Always results in a 9:3:3:1 Ratio!!! RRSS RRSs