1. 4.3 Theoretical genetics

2. Widow’s peak

3. Tongue rolling?

4. Dimples?

5. Is your earlobe attached?
Not many have free earlobes

6. Genotypes and Phenotypes
Genotype: alleles possessed by an organism
Phenotype: characteristics of an organism
Homozogous: two identical alleles of a gene
Heterozygous: two different alleles of a gene
Dominant allele: allele that has same effect on the phenotype whether it is present in the homozygous or heterozygous state
Recessive allele: allele that has an effect on the phenotype only when it is present in the homozygous state
E.g. Earlobe attachment (alleles F and f)
Genotype: FF or Ff
Phenotype: Free earlobe
Genotype: ff
Phenotype: Earlobe attached

7. 4.3 Mendel

9. Preformation
Idea that an exact miniature replica of parent existed inside sperm/egg cell

10. Mendel: The grandfather of genetics
Grew up on parents’ small farm in Austria
University of Vienna (1851)
Monastery (1857)
Breed garden peas to study inheritance
Contributions:
Factors (alleles were responsible for characteristics)
Consider probability of combination of offspring
Doppler (physicist): encourage students to learn science through experimentation
Unger (botanist): arouse Mendel’s interest in cause of variation in plants
Explain mechanism of inheritance

11. Peas Why peas? Distinct traits
Large flower allow easy manipulation of crosses

12. The flower structure
Flower has both male and female structures

13. What Mendel did

14. Mendel’s cross pollination experiment
P = Parental generation F1 = first filial generation
F2 = second filial generation
P generation = parent generation
F1 = first filial generation
Observation 1: All yellow F1

15. Punnett square

16. Test Cross
Test cross = testing a suspected homozygote by crossing it with a known homozygous recessive

17. 4.3 Blood Types

19. Review: Your blood Red blood cells: transport oxygen
White blood cells: help fight infection
Platelets: help blood clot
Plasma: medium that carries these cells

20. Each blood type has a specific…
Antigen = surface markers on your red blood cell (your blood cell’s ID)
Antibody = proteins produced by white blood cells, recognize certain antigens and trigger an immune response
Will yellow antibodies bind to green antigens?

21. What is special about the ABO blood grouping system?
Multiple alleles: IA, IB and i
Codominance: both alleles are expressed
IA, IB codominant alleles
i is recessive
Genotype
Phenotype
Protein on RBC (antigen)
Antibody in blood plasma
IAIA or IAi
Type A A
Anti b
IBIB or IBi
Type B B
Anti a
IAIB
Type AB
A and B ii
Type O
Anti a and b
What are possible genotypes (i.e. combinations of alleles)?
What phenotype result from these genotypes?
e.g. punnett cross

23. Agglutination – what happens when antigen meets specific antibody
Clumped red blood cells can crack and cause toxic reactions

24. Multiple Alleles Play the blood typing game (Quick Random Version)
Multiple Allele Practice