1. Sex-Linked Traits and Karyotypes Pre AP

2. Hemophilia Read the passage about hemophilia in dogs Read the passage about hemophilia in dogs Answer the following questions in your Bell Ringer journal Answer the following questions in your Bell Ringer journal –Do sex-linked disorders happen in humans only? –Is it important to know if a trait is sex-linked or not? Why or why not? –Does it surprise you to find that there are similar genetic disorders in dogs as humans? Explain.

3. There are traits that are controlled by one gene with 2 alleles. Often, one is dominant and the other is recessive There are traits that are controlled by one gene with 2 alleles. Often, one is dominant and the other is recessive Example: Example: widow’s peaks and dimples.

4. Some traits are controlled by a gene with multiple alleles – 3 or more for a single trait. For example: blood types and skin color in humans.

5. There are 44 chromosomes that we call autosomal chromosomes. There are 44 chromosomes that we call autosomal chromosomes. However, there are 2 chromosomes that determine our sex and we call them sex chromosomes. However, there are 2 chromosomes that determine our sex and we call them sex chromosomes. These 46 chromosomes all carrier genes on them that determine our traits. These 46 chromosomes all carrier genes on them that determine our traits.

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

7. Each egg produced by an ovary contains one X chromosome Each egg produced by an ovary contains one X chromosome Each sperm produced by a testicle contains either one X chromosome OR one Y chromosome Each sperm produced by a testicle contains either one X chromosome OR one Y chromosome The X chromosome is larger than the Y chromosome and holds more genes The X chromosome is larger than the Y chromosome and holds more genes Each animal has its own sex chromosomes and sex determination based on those chromosomes Each animal has its own sex chromosomes and sex determination based on those chromosomes

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

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

10. Sex-linked gene: Some traits are carried on the sex chromosomes. Genes on the X or Y chromosomes are sex-linked genes. Some traits are carried on the sex chromosomes. Genes on the X or Y chromosomes are sex-linked genes. This term is historically used to describe traits housed on the X chromosome This term is historically used to describe traits housed on the X chromosome These traits are passes on from parent to child. Sex- linked genes can be recessive or dominant. These traits are passes on from parent to child. Sex- linked genes can be recessive or dominant.

11. 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. 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. Fathers pass on to daughters only; mothers pass to sons and daughters Fathers pass on to daughters only; mothers pass to sons and daughters Ex. colorblindness, hemophilia, hairy ears, muscular dystrophy Ex. colorblindness, hemophilia, hairy ears, muscular dystrophy

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

13. Sex linked Punnett Squares: Question: What is the probability that a carrier female and a colorblind male will have a girl who is colorblind (b = colorblind, B = normal)? What is the probability that a carrier female and a colorblind male will have a girl who is colorblind (b = colorblind, B = normal)? YXbXb XBXB XbXb XBXbXBXb XbXbXbXb XbYXbY XBYXBY Phenotype: 25% normal boy 25% colorblind boy 25% normal girl 25% colorblind girl

14. 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 (b = colorblind, B = normal)? What is the probability that a homozygous (normal vision) female and a colorblind male will have a girl who is colorblind (b = colorblind, B = normal)?

15. XBXB XBXB XBXbXBXb XBXbXBXb XBYXBY XBYXBY XbXb Y Phenotype: 50% normal girls 50% normal boys Parents: X B X B x X b Y

16. X-Inactivation Since females have 2 X chromosomes, one is inactivated Since females have 2 X chromosomes, one is inactivated During development, each cell of the embryo randomly inactivates one During development, each cell of the embryo randomly inactivates one Every cell may have a different X inactivated (ex. Tortoiseshell Cat) Every cell may have a different X inactivated (ex. Tortoiseshell Cat) Barr-bodies - inactive X chromosomes lies along the inside of the nuclear envelope Barr-bodies - inactive X chromosomes lies along the inside of the nuclear envelope

17. Carrier – person who has one recessive allele and one dominant allele for a trait or heterozygous for that trait (only women can be carriers). Example Example Hemophiliac carrier X H X h Colorblind carrier X B X b Colorblind carrier X B X b

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

19. Reading a Pedigree Task 2: Go to the lab tables. Each person should have one answer sheet. Lets do the first one together. As a group, finish analyzing the pedigrees. If you have extra time, work on conclusion questions (homework if not completed in class). Task 1: Genotyping a pedigree chart

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21. Ticket Out Obtain a paper with a problem that asks you to create your own pedigree… due on your way out of the classroom. Obtain a paper with a problem that asks you to create your own pedigree… due on your way out of the classroom.

22. What is a karyotype? Picture of your chromosomes Picture of your chromosomes Arranged from largest to smallest Arranged from largest to smallest quickly identify chromosomal changes quickly identify chromosomal changes http://www.biology.arizo na.edu/human_Bio/activi ties/karyotyping/karyoty ping2.html http://www.biology.arizo na.edu/human_Bio/activi ties/karyotyping/karyoty ping2.html

25. Diagnose the karyotypes in the back of the room at your table. Make sure to include: Case number Boy or girl Number of chromosomes Normal or abnormal (if abnormal, what is the problem?)

26. Genetics Disorders and Mutations

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

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

29. Cystic Fibrosis Recessive genetic disorder where the body produces abnormally thick mucus in the lungs and intestines making respiration and digestion difficult Recessive 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. Body produces mucus which builds up in the breathing passages of lungs and pancreas (the organ that helps to break down and absorb food) Caused by a mutation in a gene. Body produces mucus which builds up in the breathing passages of lungs and pancreas (the organ that helps to break down and absorb food) One in four babies are born with cystic fibrosis One in four babies are born with cystic fibrosis Most common among Northern European descent Most common among Northern European descent

30. Sickle Cell Anemia Sickle cell is a recessive genetic disorder that affects the blood’s hemoglobin. Hemoglobin is the protein in your blood that carries oxygen. Sickle cell is a recessive 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 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 causes it to form clots easily and the protein doesn’t allow the red blood cell to carry very much oxygen. The ‘sickle shape’ of the cell causes it to form clots easily and the protein doesn’t allow the red blood cell to carry very much oxygen. Most common among African American descent 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)

31. Hemophilia Hemophilia is a genetic disorder in which a person’s blood clots VERY slowly or not at all. Hemophilia is a genetic disorder in which 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. A person with hemophilia can bleed to death from a paper cut or scrape. This is a recessive sex-linked disorder on the X chromosome. This is a recessive 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 is body.

32. Down Syndrome Down Syndrome is a genetic disorder that occurs when an individual receives an extra copy of a chromosome. Down Syndrome is a genetic disorder that occurs when an individual receives an extra copy of a chromosome. A mistake occurs during Meiosis I: the chromosomes failed to separate correctly (non-disjunction) therefore leaving an extra copy of chromosome #21. A mistake occurs during Meiosis I: the chromosomes failed to separate correctly (non-disjunction) therefore leaving an extra copy of chromosome #21.

33. Doctor’s use tools like amniocentesis and karyotypes to help detect most diseases. Doctor’s use tools like amniocentesis and karyotypes to help detect most diseases.

34. 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 cystic fibrosis, sickle cell anemia, Marfan syndrome, Huntington’s disease

35. 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

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

37. Types of Genetic Disorders 4. Mitochondrial –rare type of genetic disorder –caused by mutations in the non-chromosomal DNA of mitochondria

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39. Here are some genetics disorders, some you have heard about and some you haven’t.

40. Turners Syndrome 1 in 5,000 births 45 chromosomes X only #23 Monosomy Nondisjunction

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

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

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

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

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

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

47. Thirteen Q Deletion Syndrome Mentally retarded Deformed face No thumbs Heart disease Short lifespan

48. Prader-Willi Syndrome 1 in 5,000,000 births 46 chromosomes XY=97% XX=3% #15 Deletion of lower arm

49. Prader-Willi Syndrome Small bird-like head Mentally retarded Respiratory problems Obesity Short lifespan

50. Eighteen Q Deletion Syndrome 1 in 10,000,000 births 46 chromosomes XY or XX #18 Deletion of lower arm

51. Eighteen Q Deletion Syndrome Mentally retarded Heart disease Abnormal hands and feet Large eyes Large ears Normal lifespan

52. Cat-Eye Syndrome 1 in 1,000,000 births 46 chromosomes XY or XX #22 Deletion of bottom arm

53. Cat-Eye Syndrome Cat-Eye Syndrome Fused fingers and toes Mentally retarded Small jaw Heart problems Normal lifespan

54. Four-Ring Syndrome 1 in 10,000,000 births 46 chromosomes XY or XX #4 Inversion

55. Four-Ring Syndrome Cleft palate Club feet Testes don’t descend Short lifespan

56. 1 in 1,250 births 47 chromosomes XY or XX #21 Trisomy Nondisjunction Down Syndrome Trisomy

57. Down Syndrome Short, broad hands Stubby fingers Rough skin Impotency in males Mentally retarded Small round face Protruding tongue Short lifespan

58. Patau’s Trisomy Syndrome 1 in 14,000 births 47 chromosomes XY or XX #13 Trisomy Nondisjunction

59. Patau’s Trisomy Syndrome Small head Small or missing eyes Heart defects Extra fingers Abnormal genitalia Mentally retarded Cleft palate Most die a few weeks after birth

60. Edward’s Trisomy Syndrome 1 in 4,400 births 47 chromosomes XX=80% XY=20% #18 Trisomy Nondisjunction

61. Edward’s Trisomy Syndrome Small head Mentally retarded Internal organ abnormalities 90% die before 5 months of age

62. Jacob’s Syndrome 1 in 1,800 births 47 chromosomes XYY only #23 Trisomy Nondisjunction

63. Jacob’s Syndrome Normal physically Normal mentally Increase in testosterone More aggressive Normal lifespan ?

64. Klinefelter Syndrome 1 in 1,100 births 47 chromosomes XXY only #23 Trisomy Nondisjunction

65. Klinefelter Syndrome Klinefelter Syndrome Scarce beard Longer fingers and arms Sterile Delicate skin Low mental ability Normal lifespan

66. Triple X Syndrome 1 in 2,500 births 47 chromosomes XXX only #23 Trisomy Nondisjunction

67. Triple X Syndrome Normally physically Normal mentally Fertile

68. Huntington’s Disease Caused by a lethal dominant gene in which a section of DNA on chromosome #4 is repeated more than usual Caused by a lethal dominant gene in which a section of DNA on chromosome #4 is repeated more than usual Nerve cells in the brain waste away, or degenerate Nerve cells in the brain waste away, or degenerate Two forms – most common is adult onset in which those affected show no signs until 35 or 40; other is early onset Two forms – most common is adult onset in which those affected show no signs until 35 or 40; other is early onset

69. Huntington’s Disease Abnormal and unusual movements Abnormal and unusual movements Behavior changes Behavior changes Dementia that slowly gets worse, including Dementia that slowly gets worse, including Additional symptoms that may be associated with this disease: Additional symptoms that may be associated with this disease: –Anxiety, stress, and tension –Difficulty swallowing –Speech impairment In children: In children: –Rigidity –Slow movements –Tremor

70. Color-Blindness Have trouble seeing red, green, or blue or a mix of these colors Have trouble seeing red, green, or blue or a mix of these colors Caused by a recessive sex-linked allele Caused by a recessive sex-linked allele The cone cells in your eyes do not function properly or are absent The cone cells in your eyes do not function properly or are absent You may not see red, blue, or green, or you may see a different shade of that color or a different color You may not see red, blue, or green, or you may see a different shade of that color or a different color Doesn't change over time. Doesn't change over time.

71. Color-Blindness

72. Tay-sachs Autosomal recessive disorder because of mutation on chromosome 15 Autosomal recessive disorder because of mutation on chromosome 15 Infants typically appear normal until 3 to 6 months: Infants typically appear normal until 3 to 6 months: Other forms of Tay-Sachs disease are very rare. Other forms of Tay-Sachs disease are very rare.

73. Tay-sachs Disease –development slows and muscles used for movement weaken –lose motor skills such as turning over, sitting, and crawling –develop an exaggerated startle reaction to loud noises –Eventually experience seizures, vision and hearing loss, intellectual disability, and paralysis –eye abnormality called a cherry-red spot, which can be identified with an eye examination, is characteristic of this disorder. –Children with this severe infantile form of Tay-Sachs disease usually live only into early childhood.

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75. Diagnose the karyotypes cont. You have already described what is abnormal (if applicable) about the karyotypes, now you must identify what genetic disorder (if any) is portrayed using the knowledge you just received.