1. Lecture 29c Inheritance

2. Genetic Testing Predisposition to disease Alzheimer's case (Feb. 2002) Amniocentesis & Chorionic villa Family history >35 years old Donor match Paternity Forensics

3. Genetic Testing Would you want to know? Ethical concerns Cost Insurance companies see GATTACA

4. Homunculus How is “heredity passed on: Spermist vs Ovists Spermist conception of a human sperm

5. Homunculus Leeuwenhoek’s black male and white female rabbit experiments: spermist “proof”

6. Mendel’s Three Principles Dominance Segregation Independent Assortment The foundation of “classical” science (1822-1884)

7. Dominance Traits of both parents inherited, but one shows over the other Traits are not blended

8. Dominance Mechanism Two alleles are carried for each trait In true-breeding individuals, both alleles are the same (homozygous). Hybrids, on the other hand, have one of each kind of allele (heterozygous). One trait is dominant, the other trait is recessive

9. Segregation Half the gametes (egg or sperm) will carry the traits of one parent and half the traits for the other parent Pairs of alleles are separated (=segregated) during meiosis

10. Two different parental characteristics will be inherited independently of one another during gamete formation. Independent Assortment Example: flower color and leaf shape

11. Genetic Information Genes are traits “Eye color” Ear lobe connectedness Genes produce proteins Enzymes are proteins

12. Homologous Chromosomes allele: specific trait gene: location

13. Allele Example Gene = “eye color” Alleles brown blue green lavender

14. Allele Examples appearance eye color: homozygous

15. Allele Examples appearance eye color: heterozygous, brown dominant over blue

16. Genotype vs Phenotype homozygous (dominant) heterozygous homozygous (recessive) genotype phenotype appearance Phaner = visible

17. Punnett Square If male & female are heterozygous for eye color X brown:3/4 offspring blue:1/4 offspring male female

18. PKU Each parent carries one gene for PKU. Pp Pp X P p pP P P P p p P p p Possible genotypes: 1PP 2Pp 1pp Possible phenotypes:no PKUPKU

19. Compare this to what would have happened if one parent was homozygous for sickle cell. HbA HbS X HbA HbS HbA HbS HbA HbS HbA all offspring are carriers of sickle cell trait

20. Autosomes and Sex Chromosomes

21. Red-Green Color Blindness Sex-linked trait XCXC Y XCXC XcXc X XCXC XcXc YXCXC XCXC XCXC XCXC Y XcXc XCXC Y XcXc Normal male Normal female recessive gene Possible outcomes:X C X C X C X c X C YX c Y Normal female Normal Female (carrier) Normal male Color-blind male

22. Dominance Most traits show complete dominance Blending unexpected

23. Eunconnected earlobe econnected earlobe Eunconnected earlobe econnected earlobe allele gene PEE x ee gametes E e F1F1 unconnected connected

24. F1F1 Ee x Ee gametes 1/2 E 1/2 e E e Ee EEEe ee F2F2 1 EE 2 Ee 1 ee Punnett Square

25. P F1F1 F2F2 EE, ee Ee EE, 2 Ee, ee 50% 100% 75% 1:1 generation genotypes unconnected E:e Basis of the Castle-Hardy-Weinberg Law phenotypes ratio of alleles in the population

26. Genotypes Phenotypes Experiment to determine dominant vs. recessive

27. Genetic Sleuthing My eye color phenotype is brown. What is my genotype?

28. Pedigree phenotypes infer genotypes Alternative: look directly at the DNA

29. Complexities Multiple genes for one trait Example: eye color Blended traits (“incomplete dominance”) Influence of the environment

30. Disorders Down’s Syndrome (chrom 21) Huntington’s (chrom 4) Alzheimer’s (chrom 1, 10, 14, 19, 21)

32. Tongue Roller R = Tongue Roller r = Unable to Roll Tongue

33. Widow’s Peak W = Widows Peak w = Lack of Widow’s Peak

34. Free Ear Lobe Attached Ear Lobe E = Free Ear Lobe e = Attached Ear Lobe

35. Hitchhiker’s Thumb Hi = Straight Thumb hi = Hitchhiker’s Thumb

36. Bent Little Finger Bf = Bent Little Finger bf = Straight Little Finger

37. Mid-digital Hair M = Mid-Digital Hair m = Absence of Mid-Digital Hair

38. Dimples D = Dimples d = Absence of Dimples

39. Short Hallux Ha = Short Hallux ha = Long Hallux

40. Short Index Finger S s = Short Index Finger S 1 = Long Index Finger *Sex-Influenced Trait

41. Presentation created by J. Kenyon Pttttthhhhhhhtttt! Kiss me, you fool.