4. Pedigrees & Sex Linked Traits
Mrs. Ray

5. Human Chromosomes Humans have 23 pairs, 46 total chromosomes
The 23rd pair determines the sex of the organism.

6. Autosomal Traits All types of traits except for X-linked
They may be either dominant or recessive.
Examples: Hair color, eye color, attached ear lobes, hitch hiker thumb…

7. Compare Contrast Autosomal
All traits except for those linked to the X chromosome
Dominant or Recessive
Males and Females
Examples: hair & eye color, hitchhiker thumb
X-linked
Only traits linked to the X- chromosome.
Dominant or Recessive
Mostly Males
Examples: Colorblindness, baldness, hemophilia

8. Double Bubble
X-Linked vs. Autosomal

9. X Y XX XY X-linked Gene carried by the X-chromosome.
Happens mostly to males because males have only one copy of the X chromosome.
Typically Recessive traits X Y XX XY
X linked, only to males. Recessive, skips generations. 9

10. Baldness A bald man has a child with a carrier female B=Normal b=Bald
How many people are bald?
Are there any carriers? How many?
B=Normal
b=Bald

11. Xb Y XB
XBXb
XBY
XbXb
XbY

12. Colorblindness
Inability to distinguish colors-various types for example blue/green, ect.
A color blind male has children with a homozygous normal female.
How many people are colorblind?
Are there any carriers? How many?
B=Normal
b=Colorblind

13. Xb Y XB
XBXb
XBY

14. Hemophilia Inability of your blood to clot.
Effects livestock & humans
A Normal male has children with a carrier female.
How many people have hemophilia?
Are there any carriers? How many?

15. XB Y
XBXB
XBY Xb
XBXb
XbY

16. Practice Problem # 1
A stud with hemophilia is mated with a carrier mare.
How many affected offspring?
How many normal?
How many carriers?

17. Xb Y XB
XBXb
XBY
XbXb
XbY

18. Practice Problem # 2
A stud with hemophilia is mated with a mare with hemophilia.
How many affected offspring?
How many normal?
How many carriers?

19. Xb Y
XbXb
XbY

20. Practice Problem # 3
A normal stud is mated with a mare that’s a carrier for hemophilia.
How many affected offspring?
How many normal?
How many carriers?

21. XB Y
XBXB
XBY Xb
XBXb
XbY

22. Coat Color in Cats Tortoise Shell Cat Calico
Black and Orange at Same time
Males can have only one color
Calico
Black, Orange, White
Males can have white plus one color
Females can have all three

23. Practice Problem # 4 A tortoise shell female is mated to a black male.
What are the possible phenotypes?

24. XB Y
XBXB
XBY XO
XBXO
XOY

25. Practice Problem # 4
A tortoise shell female is mated to an orange male.
What are the possible phenotypes?

26. XO Y XB
XBXO
XBY
XOXO
XOY

27. Practice Problem # 5
A calico female is mated to an orange and white male.
What are the possible phenotypes?

28. XO Y XB
XBXO
XBY
XOXO
XOY

29. Practice Problem # 6 How can you get a bald female?
Create a punnett square to show how you could get a bald female.

30. Purpose of a pedigree Help to map out a given trait
Can show autosomal or X linked traits.

31. Autosomal Example
Is this a dominant or recessive trait? How do you know?
Recessive…look at alles. Does not appear in every generation. 31

32. X-linked Skips a generation Affects mostly Males
X-linked, males only. Recessive skips generation. 32

33. Mystery Trait Autosomal or X-linked? Dominant or recessive?
Autosomal Recessive 33

34. Cardiomyopathy Disease affects the heart muscle.
Autosomal or X linked?
Is this a dominant trait or recessive trait? How do you know?
Autosomal, affects both male and female. Dominant, in each generation. 34

35. Dominant or Recessive? Autosomal or X-linked?

36. Is this trait autosomal dominant or recessive?
Support with a square.

37. Is this trait autosomal dominant or recessive?
Support with a square.

38. Is this trait autosomal recessive?
Support with a Square

48. Key

49. X-linked Dominant

50. X-linked Recessive

51. Autosomal Recessive

52. Autosomal Dominant

59. Huntington's Disease Autosomal or X linked?
Is this a dominant trait or recessive trait? How do you know?
Autosomal, both sexes. Dominant, in all generations. 59