1. Mendelian Genetics

2. Vocabulary Terms 1.Allele- different forms of a gene 2.Phenotype- observable trait or characteristic 1.I.e. Green eyes, black hair 3.Genotype- genetic makeup 1.Aa, BB 4.Dominant- trait that is expressed 1.Written as capital letter 5. Recessive- only expressed when there are 2 recessive alleles Written as lower case letter 6. Heterozygous (hybrid) –Aa 7. Homozygous (purebred) –BB, bb

4. Gregor Mendel 1860’s Austrian monk who studied inheritance of traits in pea plants Called the Father of Genetics

5. Mendel’s Experiment: Test 1 Peas have 7 traits with only 2 variations per trait Example: Short or tall Test 1: Cross homozygous parents 1.Record progeny’s traits (phenotypes) Test 1: Homozygous Tall x homozygous short (TT)(tt) TT t t Result Test 1: Genotypes: Phenotypes:

6. Test 2: Cross the heterozygous progeny (offspring) 1.Record progeny’s traits (phenotypes) Test 2: Heterozygous Tall x Heterozygous Tall(Tt) T T t t Result Test 2: Genotypes: Phenotypes: Mendel’s Experiment: Test 2

7. Mendel’s Conclusions Traits are controlled by factors- genes Each factor has 2 of these forms called alleles Some are expressed as dominant –Written with a capital letter Some are expressed as recessive –Written with a lower case letter

8. Mendel’s Laws 1.Law of segregation (meiosis): Pairs of chromosomes separate during gamete formation and pair up during fertilization 2.Law of dominance: Dominant allele will be expressed 3.Law of independent assortment: Pairs of chromosomes separate unrelated to other chromosomes (differing traits are not linked to each other) 1.Example: If you have blood type O you will not automatically have brown hair

9. Punnett Squares 1.Determine alleles for gametes 2.Place alleles on grid 3.Combine alleles in boxes 4.Determine genotypes & phenotypes Example: A person with blue eyes (recessive) is crossed with another person with heterozygous brown eyes. What are the genotypes & phenotypes of their progeny? Genotypes: Phenotypes: Alleles: