Genetics the scientific study of heredity

1. Genetics the scientific study of heredity

2. How do we get our traits? Why are we tall, short, blonde? What makes us; us? Hitchhiker’s Thumb Slater with his dimples

3. Human Traits & Genetics • Every living thing – plant or animal, microbe or human being – has a set of characteristics inherited from its parent or parents. • How do genes work? What are they made of, and how do they determine the characteristics of organisms?

4. Gregor Mendel • Gregor Mendel “Father of Genetics” (1864) - Austrian Monk, studied Heredity He preformed experiments with these pea plants by forcing plants with different traits to pollinate each other. Parents – first generation pollinated F1 – first offspring F2 – Second offspring

5. Traits • Alleles – Gene form, Y or y, for each variation of a trait of an organism. • Dominant – visible, observable trait of an organism that masks a recessive form of a trait. • Recessive – A hidden trait of an organism that is masked by a dominant trait.

6. Genotype and Phenotype • Genotype – the gene combination of an organism. • Phenotype – the way an organism looks and behaves. Physical characteristics of an organism.

7. Gregor Mendel • Mendel observed seven traits that are easily recognized and apparently only occur in one of two forms: 1. flower color is purple or white 2. seed color is yellow or green 3. flower position is axil or terminal 4. pod shape is inflated or constricted 5. stem length is long or short 6. pod color is yellow or green 7. seed shape is round or wrinkled

8. Law of Segregation After noticing that the allele for green seeds reappeared in the second generation, Mendel concluded that the two alleles for each trait must separate when gametes are formed. • Law of Segregation – In other words, A parent only passes one form of a gene or allele (i.e. either A or a but not both) at random to each offspring.