1. Chapter 12 Patterns of Heredity and Human Genetics

2. 12.1 Mendelian Inheritance of Human Traits Pedigree – made up of a set of symbols that identify males and females, the individuals affected by a trait being studied and family relationships (Family Tree)

5. Pedigree

6. Simple Recessive Heredity Cystic Fibrosis (CF) –Lethal genetic disorder among whites –Thick mucus in lungs and digestive tract –Defective protein in the plasma membrane –Physical therapy and special diet used to treat

7. Simple Recessive Heredity Tay Sachs Disease –Recessive disorder of the central nervous system –Missing enzymes that breaks down lipids –Causes blindness, progressive loss of movement and mental deterioration

8. Simple Recessive Heredity Phenylketonuria (PKU) –Missing enzyme needed to break down amino acid phenylalanine to a different amino acid tyrosine –Damages central nervous system –Cannot break down milk, results in retardation

9. Dominant Hereditary Conditions Tongue Rolling Hapsburg Lip - The lower lip and chin protrude, sometimes forcing the mouth open. Earlobe (Free-hanging) Hitchhiker’s Thumb Thick Lips Huntingtons Disease Double Jointedness

10. Huntington Disease Lethal, appears between ages 30 – 50 Breakdown of portions of the brain

11. 12.2 Incomplete Dominance –Inheritance pattern where the phenotype of a heterozygote is intermediate between those of the 2 homozygotes; neither allele of the pair is dominant but combine and display a new trait

12. Incomplete Dominance Ex. –RR (Red Flowers) x R’R’ (white flowers) = F1 offspring are pink RR R'RR' R'RR'

13. Codominance Two different uppercase letters, phenotypes of both homozygotes to be produced in heterozygous individuals. Both Alleles expressed equally.

14. Morgan 1. Responsible for sex determination, linkage and sex-linkage 2. Concluded that all organisms have: –Autosomes – non-sex chromosomes that carry all characteristics except sex –Sex Chromosomes – two chromosomes that determine sex –XX – Female, X is rod shaped –XY – Male, Y is J or hook shaped

15. Humans – 46 chromosomes Autosomes – 44 chromosomes Sex Chromosomes – 2 chromosomes Drosophila – 8 chromosomes Autosomes – 6 chromosomes Sex Chromosomes – 2 chromosomes

16. Sex Linked Traits Traits controlled by genes located on sex chromosomes Polygenetic Inheritance –Inheritance controlled by two or more genes found on same or different chromosomes –Ex. Stem length in plants

17. Environment can play a major role in genetics 1. Internal factors – Hormones 2. External factors –Temperature –Nutrition –Light –Chemicals –Infectious agents