4.3 Theoretical genetics

Widow’s peak

Tongue rolling?

Dimples?

Is your earlobe attached? Not many have free earlobes

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

4.3 Mendel

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

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

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

The flower structure Flower has both male and female structures

What Mendel did

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

Punnett square

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

4.3 Blood Types

http://www.bbc.co.uk/news/magazine-20170787

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

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?

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

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

Multiple Alleles Play the blood typing game (Quick Random Version) http://www.nobelprize.org/educational/medicine/bloodtypinggame/ Multiple Allele Practice