1. MENDELIAN GENETICS Unit Four

2. Gregor Mendel Discovered principals of genetics Used peas to prove his inheritance theory Before Mendel, people thought you were a blend of you parents (blending theory).

3. Vocabulary ALLELE- an alternate form of the same gene GENOTYPE-A letter for the allele DOMINANT ALLELE- Capital letter, “masks” a recessive allele RECESSIVE ALLELE- lower case letter, only expressed if both are recessive PHENOTYPE- Physical characteristics Hair Color (trait) Brown hair (allele) Blonde hair (allele) T t

4. Genotype T t t t T T Homozygous DominantHeterozygousHomozygous Recessive

5. T t t t T T Blonde Hair Red Hair Phenotype

6. Types of Inheritance 1. Dominant and Recessive Monohybrid cross Dihybrid cross 2. Sex linked inheritance 3. Codominance 4. Incomplete dominance

7. Dominant and Recessive Inheriting genes on chromosome 1-22- called autosomes Use upper case and lower case letters Monohybrid and dihybrid crosses AA, Aa, aa (monohybrid) AABb (dihybrid)

8. Sex-Linked Inheritance Inheriting genes through sex chromosome X Y chromosomes does not contain many Alleles X A X a, X a Y