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Sex-Linked Inheritance

Sex-Linked Inheritance. Sex determined by genes found on the X and Y chromosome Females: egg produced with an X chromosome. Sex Determination. Sex determined by genes found on the X and Y chromosome Females: egg produced with an X chromosome

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Sex-Linked Inheritance

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  1. Sex-Linked Inheritance

  2. Sex determined by genes found on the X and Y chromosome Females: egg produced with an X chromosome Sex Determination

  3. Sex determined by genes found on the X and Y chromosome Females: egg produced with an X chromosome Males: ½ sperm cells contain X; and the other ½ contain Y Sex Determination

  4. Sex determined by genes found on the X and Y chromosome Females: egg produced with an X chromosome Males: ½ sperm cells contain X; and the other ½ contain Y There is a 50/50 chance of child being a boy/girl Sex Determination X X X Y X X X X 50% Girl 50% Boy X Y X Y

  5. Defined: Inherited conditions found on X chromosome Usually recessive Females: XX chromosomes XHXH= healthy XHXh= healthy carrier XhXh= disease Males: XY chromosomes XHY = healthy XhY = disease Rare in women (back-up X chromosome) Sex-Linked Disorders XHXH XH Y XHXh Xh Y XhXh H = healthy h = disorder

  6. Defined: Inherited conditions found on X chromosome Usually recessive Females: XX chromosomes XHXH= healthy XHXh= healthy carrier XhXh= disease Males: XY chromosomes XHY = healthy XhY = disease Rare in women (back-up X chromosome) Examples of disorders: Sex-Linked Disorders Duchene Muscular Dystrophy Hemophilia Colorblindness

  7. Types of Colorblindness

  8. Deuteranopia (2.7%) Normal

  9. Protanopia (0.59%) Normal

  10. Tritanopia (0.016%) Normal

  11. Colorblind Test:Do you see a number inside the picture? 53

  12. Colorblind Test:Do you see a number inside the picture? 12

  13. Colorblind Test:Do you see a number inside the picture? 6

  14. Colorblind Test:Do you see a number inside the picture? 74

  15. Colorblind Test:Do you see a number inside the picture? 6

  16. Hemophilia and the Royal Family

  17. What is the probability of: a. Daughter with hemophilia? 0% b. Carrier child? 25% c. Child with hemophilia? 25% d. Two healthy children? 9/16 (56%) 1 min: Discuss with your neighbor.Jen is a healthy carrier (XH Xh) of hemophilia and Adam has no history in his family (XH Y). Healthy girl Healthy boy Healthy girl (carrier) Hemophiliac boy 2010 2013 x ¾ ¾

  18. What is the probability of getting a: a. Healthy son? 25% b. Healthy daughter? 25% c. Child with hemophilia? 50% d. Carrier child? 25% Hemophilia is a sex linked disorder. Kelly does not have hemophilia even though her mother did. Jim (Kelly’s husband) is a hemophiliac. Their first child Barry is healthy but their other child Rachel is a hemophiliac. Draw a Pedigree for this family and a Punnett square for Jim and Kelly. Xh Xh Kelly’s mother Kelly Jim XH Xh Xh Y Barry Rachel Healthy girl (carrier) Healthy boy Xh Xh XH Y Hemophiliac girl Hemophiliac boy

  19. Key XH = healthy Xh = hemophilia Sex linked recessive: Hemophilia 2 1 XHY 4 6 3 5 7 XHY Xh Y XHY 9 12 8 10 11 13 Males: XH Y or Xh Y XHY XHY Xh Y XHY 14 Xh Y Hint: Only 1 person is unknown.

  20. Key XH = healthy Xh = hemophilia Sex linked recessive: Hemophilia 2 1 Y Xh XHY XH Xh 4 6 3 5 7 XHY Xh Y XHY XH XH from mother from father 9 12 8 10 11 13 Females: XHXH or XHXh or XhXh XHY XHY Xh Y XHY XH XH 14 Xh Y Hint: Only 1 person is unknown.

  21. Key XH = healthy Xh = hemophilia Sex linked recessive: Hemophilia 2 1 XHY XH Xh 4 6 3 5 7 Xh Y XHY Xh Y XHY XH XH Xh 9 12 8 10 11 13 Females: XHXH or XHXh or XhXh XHY XHY Xh Y XHY XH XH from father 14 from mother Xh Y Hint: Only 1 person is unknown.

  22. Key XH = healthy Xh = hemophilia Sex linked recessive: Hemophilia 2 1 XHY XH Xh 4 6 3 5 7 XHY Xh Y XHY XH XH Xh 9 12 8 10 11 13 Y Xh Females: XHXH or XHXh or XhXh XHY XHY Xh Y XHY XH Xh XH 14 Xh Y from father from mother

  23. Key XH = healthy Xh = hemophilia Sex linked recessive: Hemophilia 2 1 XHY XH Xh 4 6 3 5 7 Xh XH XHY Xh Y XHY XH Xh XH Xh 9 12 8 10 11 13 Females: XHXH or XHXh or XhXh XHY XHY Xh Y XHY XH Xh XH 14 from father from mother Xh Y Hint: Only 1 person is unknown.

  24. Key XH = healthy Xh = hemophilia Sex linked recessive: Hemophilia 2 1 XHY XH Xh 4 6 3 5 7 XH XHY Xh Y XHY XH Xh XH Xh 9 12 8 10 11 13 Females: XHXH or XHXh or XhXh XHY XHY Xh Y XHY XH Xh XH X? 14 from mother from father Xh Y Hint: Only 1 person is unknown.

  25. Quiz • How are sex-linked disorders different from autosome disorders? • Why are sex-linked disorders more common in males? • Write the genotype of a heterozygous female. • Write the genotype of a carrier female. • Examine Kelly and Jim’s Punnett square. What are the chances they would have three children, all of whom are healthy?

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