1. Chapter 8 Mendel & Heredity

2. Chapter Overview 8.1 Mendel’s Experiment
8.2 Theory and Law of Heredity
8.3 Punnett Squares
8.4 Complex Patterns of Heredity

3. Topic #1-8.1 Origin of Genetics
1800s before DNA
Gregor Mendel
Austrian monk intrigued with “heredity”
Passing of traits from parents to offspring
Designed an experiment to show how “genes” were passed down
Bred pea plants for color patterns 7 years
Observed inheritance patterns

4. Topic #2- Mendel’s Experiment
Monohybrid Cross
1 trait flower color
Based on this experiment he came up with 4 hypotheses…

5. Mendel’s Hypotheses
1. Alternating forms of genes called alleles

6. Mendel’s Hypotheses 2. For each trait organism has 2 alleles
Same 2 alleles = homozygous (AA, aa)
Different alleles = heterozygous (Aa)

7. Mendel’s Hypotheses
3. When only 1 of the 2 traits in a heterozygous organisms is visible the allele is dominant (R) the non visible is recessive (r)
You only see “white” when
There are 2 small letters
(homozygous recessive)
Because the large letter
isnt there to block it from showing

8. Mendel’s Hypotheses
4. The 2 alleles for a character separate during meiosis (gametes) Principle of segregation!!

9. Topic #3- What Mendel’s Experiment Show Us Today
Every organism has a genotype
Genetic makeup (AA, Aa, aa)
Every organism has a phenotype
Observable (Purple, Purple, White)

10. REVIEW What are the genotypes for What is a Genotype?
Homozygous dominant:
Heterozygous:
Homozygous recessive:
What is a Genotype?
What is a Phenotype?
What is an Allele? AA Aa aa

11. Monohybrid Practice problems
Cross H. Dominant X Heterozygous
Cross H. Recessive X Heterozygous
Cross Heterozygous X Heterozygous
Cross H. Dominant X H. Recessive
Practice Worksheet