Passing on genetic information from parents to children

1. Passing on genetic information from parents to children An explanation of X- linked inheritance

2. Here are some PowerPoint teaching slides which demonstrate the transmission of an x-linked inherited condition from parent to child; please feel free to use these within your teaching Some parts of the animations run automatically; others require a mouse click Most slides have notes with further information

3. The 46 human chromosomes seen down the microscope Hundreds of genes are located on each chromosome (The dark bands on the chromosomes are due to a special staining technique and are not genes as these are too small to see)

4. The 46 human chromosomes arranged in their 23 pairs

5. male The 46 human chromosomes arranged in their 23 pairs Sex chromosomes of a

6. male female The 46 human chromosomes arranged in their 23 pairs Sex chromosomes of a

7. Position of particular gene Males Y chromosome X chromosome Females X chromosome

8. X-linked inheritance where the mother is a carrier for an X-linked recessive condition

9. Males Altered gene Male with an X-linked recessive condition Y chromosome X chromosome Females Usual gene Altered gene Female who is a carrier for an X-linked recessive condition X chromosome

10. X-linked recessive inheritance where the mother is a carrier Parents Father Mother Sperm/Eggs X Y X X At conception Son Daughter Daughter Son

11. X-linked recessive inheritance where the mother is a carrier Parents Father Mother Sperm/Eggs X Y X X Female, does not have the condition, non-carrier Female, carrier for the condition Male, does not have the condition Male, has the condition

12. X-linked inheritance where the father has an X-linked recessive condition

13. X-linked recessive inheritance where the father has an X-linked condition Parents Father Mother Sperm/Eggs X Y X X At conception Son Daughter Daughter Son

14. X-linked recessive inheritance where the father has an X-linked condition Parents Father Mother Sperm/Eggs Male, does not have the condition Female, carrier for the condition

15. Only a few disorders are known to be inherited in an X-linked dominant manner. X-linked dominant inheritance

16. X-linked dominant inheritance where the mother has the condition

17. Males Altered gene Male with an X-linked dominant condition Y chromosome X chromosome Females Altered gene Usual gene Female who has an X-linked dominant condition X chromosome

18. X-linked dominant inheritance where the mother has the condition Parents Hascondition Unaffected Mother Father Sperm/Eggs X Y X X At conception Son Daughter Daughter Son

19. X-linked dominant inheritance where the mother has the X-linked condition Parents Hascondition Unaffected Mother Father Sperm/Eggs X Y X X At conception Son without condition Son with condition Daughter with condition Daughter without condition

20. X-linked dominant inheritance where the mother has the X-linked condition Parents Hascondition Unaffected Mother Father X-linked dominant conditions may be so severe that males with the condition do not survive Daughter with condition Daughter without condition Son without condition Son with condition

21. X-linked dominant inheritance where the mother has the X-linked condition Parents Hascondition Unaffected Mother Father So fewer males than expected may be seen in the children of a mother who has an X-linked dominant condition Daughter with condition Daughter without condition Son without condition

22. This animation is part of a series describing modes of inheritance To access these and other resources for teaching and learning genetics, please visit: www.geneticseducation.nhs.uk