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Human Heredity

Human Heredity. Some where on your notes…number 1 – 5. Don’t let anyone see your answers….prizes will be given for the highest score 1. NAME THIS MOVIE!. There are traits that are controlled by one gene with 2 alleles. dominant and recessive Example:

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Human Heredity

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  1. Human Heredity

  2. Some where on your notes…number 1 – 5. Don’t let anyone see your answers….prizes will be given for the highest score 1. NAME THIS MOVIE!

  3. There are traits that are controlled by one gene with 2 alleles. • dominant and recessive • Example: widow’s peak and dimples.

  4. Some traits are controlled by a gene with multiple alleles – 3 or more for a single trait. Examples: blood types and skin color in humans alleles=A, B, O

  5. There are 44 chromosomes that we call autosomal chromosomes. • There are 2 chromosomes that determine our sex = sex chromosomes. • These 46 chromosomes all carry genes on them that determine our traits.

  6. Out of our 23 pairs of chromosomes, 1 pair is the sex chromosomes • (X and Y). • Female = XX • Male = XY

  7. Question: What is the probability that your parents will have a boy or girl? • XY (dad) x XX (mom) Y X Genotype: 50% XX 50% XY X XX XY Phenotype: 50% boy 50% girl X XX XY

  8. 2. NAME this MOVIE

  9. Question? If my parents have 5 boys in a row, what is the chance they will have a girl the next time? 50%

  10. Human genes are inherited • Some traits are controlled by one gene. • Study inheritance of traits through a pedigree. • A pedigree is a chart or “family tree” that tracks a specific trait.

  11. Pedigree Symbols

  12. Genetic counselors analyze PEDIGREES to infer about genotypes of family member. Dominant gene: →affected individuals have at least one affected parent →the phenotype generally appears every generation

  13. Recessive gene: →unaffected parents can have affected offspring →affected progeny are both male and female

  14. Sex-linked gene: • Some traits are carried on the sex chromosomes. Genes on the X or Ychromosomes are sex-linked genes. • These traits are passed on from parent to child. Sex- linked genes can be recessive or dominant. • MALES are more likely to have a sex-linked trait because they only have ONE X and Y. The allele is USUALLY on the X chromosome. • Ex. colorblindness, hemophilia, hairy ears, muscular dystrophy

  15. Are you colorblind? What numbers do you see?

  16. Carrier – person who has one recessive allele and one dominant allele for a trait or heterozygous for that trait (only women can be carriers). Examples: Hemophiliac carrier XHXh Colorblind carrier XBXb

  17. Carriers do not show that particular trait phenotypically but have a chance to pass the trait on to their child. Carrier – half colored

  18. Reading a Pedigree Recessive trait Autosomal Dominant

  19. YO Sex linked Punnett Squares: Question: What is the probability that a carrier female and a colorblind male will have a girl who is colorblind (Xb = colorblind, XB = normal)? Xb YO Phenotype: 25% normal boy 25% colorblind boy 25% normal girl 25% colorblind girl XBXb XBY XB Xb XbXb XbY

  20. Try this one on your own Question: What is the probability that a homozygous (normal vision) female and a colorblind male will have a girl who is colorblind (Xb = colorblind, XB = normal)?

  21. 3. NAME this MOVIE

  22. Parents: XBXB x XbY Xb Y Phenotype: 50% normal girls 50% normal boys XBXb XBY XB XB XBXb XBY

  23. ?

  24. Genetics Disorders and Mutations

  25. Mutations … • are changes in the genetic material • can be good or bad • can be on a single gene or the whole chromosome

  26. Genetic Disorder – abnormal condition that a person inherits through genes or chromosomes. They are caused by mutations or changes in a person’s DNA. Write down 3 disorders that have affected someone you know.

  27. 4. NAME this MOVIE

  28. Cystic Fibrosis • Genetic disorder where the body produces abnormally thick mucus in the lungs and intestines making respiration and digestion difficult • Caused by a mutation in a gene. The product of this gene is a chloride ion channel important in creating sweat, digestive juices and mucus. • One in four babies are born with cystic fibrosis • Most common among Northern European descent

  29. Sickle Cell Anemia • Sickle cell is a genetic disorder that affects the blood’s hemoglobin. Hemoglobin is the protein in your blood that carries oxygen. • Sickle-cell anemia is caused by a point mutation in protein chain of hemoglobin, replacing the amino acid glutamic acid with the amino acid valine • The ‘sickle shape’ of the cell doesn’t allow the red blood cell to carry very much oxygen. • Most common among African American descent Famous People with Sickle Cell Disease Miles Davis, jazz musician. Paul Williams, singer (The Temptations) Georgeanna Tillman, singer (The Marvelettes) Tionne "T-Boz" Watkins, singer (TLC)

  30. Hemophilia • A person’s blood clots VERY slowly or not at all. • A person with hemophilia can bleed to death from a paper cut or scrape. • This is sex-linked disorder on the X chromosome. • Queen Elizabeth suffered from this disorder. This man received a vaccine. This is what having hemophilia did to his body.

  31. Down Syndrome • occurs when an individual receives an extra copy of a chromosome. • A mistake occurs during Meiosis I or II: the chromosomes failed to separate correctly (non-disjunction) therefore leaving an extra copy of chromosome #21.

  32. Doctor’s use tools like amniocentesis and karyotypes to helpdetect most diseases.

  33. ?

  34. What is a karyotype? • Picture of your chromosomes • Arranged from largest to smallest • quickly identify chromosomal changes

  35. 4 Types of Genetic Disorders 1. Single gene • Change in the DNA sequence • More than 6000 known disorders • Autosomal or sex linked • 1 in 200 births Examples: cystic fibrosis, sickle cell anemia, Marfan syndrome, Huntington’s disease

  36. Types of Genetic Disorders 2. Multi-factoral • combination of environmental factors and mutations in multiple genes • more complicated Examples: heart disease, high blood pressure, Alzheimer’s disease, arthritis, diabetes, cancer, and obesity

  37. 5. NAME this MOVIE

  38. Types of Genetic Disorders 3. Chromosomal • abnormalities in chromosome structure as missing or extra copies or gross breaks and rejoining Example: Down Syndrome

  39. Types of Genetic Disorders 4. Mitochondrial • rare type of genetic disorder • caused by mutations in the non-chromosomal DNA of mitochondria (inherited through Mom)

  40. Here are some genetics disorders: some you have heard about and some you haven’t.

  41. Turners Syndrome 1 in 5,000 births 45 chromosomes X only #23 MonosomyNondisjunction

  42. Turners Syndrome 96-98% do not survive to birth No menstruation No breast development No hips Broad shoulders and neck

  43. Cri-Du-Chat Syndrome 1 in 216,000 births 46 chromosomes XY or XX #5 Deletion of lower arm

  44. Cri-Du-Chat Syndrome Moon-shaped face Heart disease Mentally retarded Malformed larynx Normal lifespan

  45. Aniridia-Wilms Tumor Syndrome 1 in 50,000,000 births 46 chromosomesXY or XX #11 Deletion of upper arm

  46. Aniridia-Wilms Tumor Syndrome Mentally retarded Growth retarded Blindness Tumors on kidneys Short lifespan

  47. Thirteen Q Deletion Syndrome 1 in 500,000 births 46 chromosomesXY or XX #13 Deletion of lower arm

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