1 / 55

Beyond Mendel, Sex Linkage, Human Genetics

Beyond Mendel, Sex Linkage, Human Genetics. Mendel studied only simple inheritance WELL-DEFINED, DOM/REC. Non-Mendelian Inheritance Patterns. Incomplete Dominance: INTERMEDIATE HET (Rr = PINK). Homework - perform P, F1, F2 crosses USING SNAPDRAGONS.

ishana
Download Presentation

Beyond Mendel, Sex Linkage, Human Genetics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Beyond Mendel, Sex Linkage, Human Genetics

  2. Mendel studied only simple inheritance WELL-DEFINED, DOM/REC

  3. Non-Mendelian Inheritance Patterns

  4. Incomplete Dominance: INTERMEDIATE HET (Rr = PINK)

  5. Homework - perform P, F1, F2 crossesUSING SNAPDRAGONS

  6. Multiple Alleles: some genes haveMORE THAN TWO ALLELES

  7. Understand: A, B, O BLOOD TYPING

  8. Understand: A, B, O BLOOD TYPING

  9. Understand: A, B, O BLOOD TYPING

  10. Understand: A, B, O BLOOD TYPING

  11. Understand: A, B, O BLOOD TYPING

  12. Codominance: both alleles EXPRESSED/DETECTED (e.g. AB)

  13. Nature/Nurture: environment INFLUENCES PHENOTYPE

  14. Morgan, Flies, Sex Linkage - 1910sGenes Shown on Chromosomes

  15. By now, scientists could see CHROMOSOMES AND MEIOSIS

  16. Drosophila melanogaster: FRUIT FLY

  17. Autosomes (flies have 3 pairs): NOT GENDER DETERMINING

  18. Sex Chromosomes (flies have 1 pair): GENDER DETERMINING, X AND Y

  19. Wild Type: DOMINANT (e.g. RED EYES)Mutant: RECESSIVE (e.g. WHITE EYES)

  20. Cross 1: True Parentals RED FEMALE X WHITE MALE

  21. At first, Morgan assumed eye color was autosomal/Mendelian: F1 = Rr, F2 = 3:1

  22. But F2 was half unexpected: where all females red, MALES 50:50 RED:WHITE

  23. Morgan formed a new hypothesis: GENE FOR EYE COLOR ONLY ON X

  24. Rule Three: For sex linkage, show alleles on X’s (e.g. XR) - none on Y’s. Prediction must include gender. Use Mendelian letters for genes - not Morgan’s (+/-) naming system.

  25. Let’s Show the P X P Cross to F1P Gametes: red/female X white/male

  26. Let’s Show the P X P Cross to F1P Gametes: red/female X white/male

  27. Predictions: 50% RED FEMALES50% RED MALES

  28. Let’s Show the F1 X F1 Cross to F2F1 Gametes: Het/Female X Red/Male

  29. Let’s Show the F1 X F1 Cross to F2 F1 Gametes: het/female X red/male

  30. Predictions: 50% RED FEMALES25% RED MALES; 25% WHITE MALESIs this consistent with observations?

  31. Some Human Genetics

  32. Pedigree Analysis: MASTER ALL RULESMake sure you define shaded trait OR write phenotype below each person.

  33. The following FYI traits are NOT on exam.

  34. Sickle Cell Anemia • REC AUTOSOMAL - SOME INC DOM • African Americans - 1/400 • Carriers - 1/10 • Defective HEMOGLOBIN CHAIN • Hom/Rec = LETHAL; Het = WEAK Protects against tropical malaria - thus, selected among many equatorial races.

  35. Cystic Fibrosis • REC AUTOSOMAL • European Caucasions - 1/2500 • Carriers - 1/24 • Defective Na/Cl TRANSPORTER • High levels of secreted SALT, MUCUS • If untreated, LETHAL BY AGE 5

  36. Huntington Disease • DOM AUTOSOMAL • Unstable - EXPANDING MUTATION • 30,000 HAVE, 150,000 AT RISK • Gene function unclear • Degenerative BRAIN FUNCTION • No good treatment - LETHAL 35-45

More Related