1 / 45

Mendelian Inheritance Part 2

Mendelian Inheritance Part 2. BIO 2215 Oklahoma City Community College. Dennis Anderson. Multiple Alleles. More than two forms of an allele exist in a population An individual only has two of the alleles. Multiple Blood Alleles. A allele for making the A antigen on red blood cells.

quito
Télécharger la présentation

Mendelian Inheritance Part 2

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. Mendelian InheritancePart 2 BIO 2215 Oklahoma City Community College Dennis Anderson

  2. Multiple Alleles • More than two forms of an allele exist in a population • An individual only has two of the alleles

  3. Multiple Blood Alleles A allele for making the A antigen on red blood cells B allele for making the B antigen on red blood cells O allele for NOT making the A or B antigen on red blood cells

  4. Three alleles give four blood types AA or AO = Type A blood BB or BO = Type B blood AB = Type AB blood OO = Type O blood

  5. California Court Case • 1946 the California supreme court ruled that Charlie Chaplin was the biological father of a child he claimed was not his. • His defense was that the baby had type B blood. He had type A and the woman who sued him had type O (These may not be the actual blood types, but it illustrates the point) • Was the court correct?

  6. AA, AO = Type A BB, BO = Type B AB = Type AB OO = Type O AO AO OO OO O O A O The judge should take a course in zoology!

  7. Mutation • Change in a gene • nucleotide sequence is often altered • Produce abnormal protein • Cause a disease (sickle cell anemia) • Resistance to a disease (AIDS)

  8. Levels of Mutation • Molecular level • Deletion of nucleotides • Addition of nucleotides • Substitution of nucleotides • Chromosomal level • Change in structure • Change in number of chromosomes

  9. Mutant Has different phenotype because of a change in his DNA Normal Mutant • Unusual phenotype • Mutations cause mutants

  10. Hemoglobin • Protein molecule made of 4 globin chains • 2 alpha chains with 141 amino acids • 2 beta chains with 146 amino acids

  11. Sickle Cell Anemia • Gene for making hemoglobin is changed from normal

  12. Valine Valine Histidine Histidine Glutamic acid Valine Leucine Proline Proline Leucine Thre.. Thre.. CAC One nucleotide has changed Normal Hemoglobin Beta ChainFirst six amino acids CTC Hemoglobin S Beta ChainFirst six amino acids

  13. Hemoglobin S • Forms long rod like molecules that stretch RBC into a sickle shape • Sickled cells obstruct circulation of blood • Allele for hemoglobin S is recessive • SS = Normal • Ss = Carrier • ss = Sickle cell anemia

  14. Why is the s allele more common in Blacks than Whites? • Ancestors of Blacks lived in areas where malaria was present • Malaria parasite cannot survive on hemoglobin S • Even Ss are immune to malaria • The s allele is beneficial in an environment where malaria is present

  15. Beta Globin Mutations • Over 300 different mutations!

  16. Causes of Mutations • Spontaneous • Random • About 1/100,000 chance of a gene mutating • Induced • Caused by mutagens • X-rays…break DNA • UV radiation….Thymine dimers • LSD…Break chromosomes • Cigarette smoke…damages tumor suppressor genes

  17. Spontaneous Mutation • Two people of normal height have a child with dwarfism • Bacteria become resistant to antibiotics • Cold virus mutates every year • Immunity for this years cold will not protect you from next years cold • AIDS virus mutates too fast to make a conventional vaccine

  18. A C A T T G T C A C A G T C T T Ultraviolet LightCauses adjacent Thymines to bond together

  19. A C A G T C T T Excision Repair EnzymeRemoves small section of DNA

  20. DNA Polymerase fills in missing nucleotides A C A T T G T C Excision RepairRemoves small section of DNA A C T C

  21. Xeroderma Pigmentosum • Skin blisters from sun exposure • Develop skin cancer as children • Recessive gene does not produce DNA repair enzyme

  22. Sunlight Exposure Increases the Risk of Skin Cancer • DNA repair enzymes do not always fix the damage that sunlight inflicts on DNA of skin cells. • The more a person is exposed to sunlight, the greater the risk of skin cancer

  23. Homologous chromosomes line up in a double file in metaphase I of meiosis

  24. Homologous Pairs Separate

  25. Four Gametes With Single Chromosomes

  26. Fertilization

  27. Nondisjunction One pair of chromosomes fails to separate during meiosis

  28. Trisomy Zygote ends up with 3 chromosomes instead of 2 for a given chromosome pair.

  29. Karyotype • Picture of chromosomes • Often arranged with autosomes in descending order and sex chromosomes separate

  30. Normal Male

  31. Normal Female

  32. Trisomy 21Down Syndrome

  33. Down Syndrome • Large tongue • Flat face • Single crease across palm • Slanted eyes • Mental retardation • Some are not

  34. Maternal Age & Down Syndrome

  35. Trisomy 18Edward Syndrome

  36. Edward Syndrome • Heart defects • Displaced liver • Abnormal hands • Low-set ears • Severe retardation • 98% abort • Lifespan < 1 year

  37. Trisomy 13Patau Syndrome

  38. Patau Syndrome • Cleft lip and palate • Extra fingers & toes • polydactylism • Defects • Heart • Brain • Kidney • Most abort • Live span < 1 month

  39. Klinefelter Syndrome

  40. Klinefelter Syndrome • Breast development • Small testes • Sterile • Low intelligence • Not retarded Klinefelter Website

  41. Turner Syndrome

  42. Turner Syndrome • Short • Not go through pruberty • Produce little estrogen • Sterile • Extra skin on neck

  43. Abnormal Chromosome Numbers • Aneuploidy • Missing or extra chromosome • Polyploidy • Extra set of chromosomes • Usually lethal • Common in cancer • Common in plants

  44. Fetal testing can determine abnormal karyotypes

  45. The End

More Related