More Patterns of Inheritance

1. More Patterns of Inheritance

2. Incomplete Dominance • A cross where neither allele is dominant over the other. • The traits appear to be blended together.

3. Ex. Snapdragon flowers • RR=Red • WW=white • RW=pink

5. Bay is brown with black. The Cream Dilution Gene Is white when homozygous. What will it do to horses?

6. brown with black. CREAM and BROWN produce New color: BUCKSKIN

7. What Pattern of Color Inheritance Does this show? Cream dilutes red-brown To make….

8. PALOMINO, a golden color.

9. Incomplete Dominance

10. Codominance • A cross where both alleles are equally expressed.

11. Ex. Horse Coats • CBCB=Brown coat • CWCW=White coat • CBCW=Roan coat: has both brown and white hairs.

13. Co-dominance

14. Andalusian Chickens • Black feathers and white feathers are co-dominant. • Cross FB FB and FW FW and what will be produced?

15. Andalusian Chickens Q: Cross FB FB and FW FW and what will be produced? A: A Steel Blue Chicken FB FW

16. Do this: • Cross a heterozygous red rose with a homozygous recessive yellow rose. Red is the dominant allele. What are the possible colors of offspring?

17. X What will the offspring look like?

18. 2. A farmer is planning to mate a bull and cow. The male has a roan coat (brown and white hairs) and the female has a white coat (white hairs). What might their calves look like?

19. X What will the offspring look like?

20. 3. Your parents have decided to plant some snapdragons and want to know why there are three colors – red, pink and white. You volunteer to explain it to them by showing them the cross of 2 hybrid pink snap dragons – what are the possible offspring?

22. You and your partner carry sickle cell trait. What are your chances of having a baby with sickle cell anemia? Use RR for normal blood. RS for carriers and SS for sickle cell anemia.

23. Sickle Cell Anemia Normal Carrier

24. Two heterozygous parents with free earlobes have 4 children predict the genotypes and phenotypes for the children’s ears. F = free ear lobes ff = attached ear lobes

25. X Hybrid Hybrid

26. X Hybrid Hybrid

27. Warm-Up • No blurting – give everyone a chance • Decide if the pictures are examples of: • Simple dominance • Incomplete dominance • Codominance

29. Andalusian Chickens

31. Warm-Up • Complete this problem in your journal: • If a man an a woman are having a baby, what are the chances the baby will be a boy? Use a Punnett Square to justify your answer. Hint: Think about which chromosomes a male has and which ones a female has

32. Blood Types are an example of co-dominance

33. Human Blood Types

34. Blood type rules • A is dominant over O • B is dominat over O • O is recessive to A and B • A and B are co-dominant to each other.

35. X-Linked Genes • Genes that are located on the X sex chromosomes. • Males will have one copy of the gene. Normal male- XB Y Affected Male- Xb Y • Females Will have 2 copies of the gene: Normal Female – XB XB “Carrier” Female – XB Xb Affected Female – Xb Xb

37. Y X Gender Determination • (Very few genes are found on the Y Chromosome) • Only females can be carriers for sex-linked disorders on the X. Carrier – a person who transports the recessive allele but does not show the recessive trait. *Are they heterozygous or homozygous?*

38. X Chromosome • Recessive genes found there: • Colorblindness Xc • Baldness Xb • Hemophilia - bleeding disorder where blood won’t clot. Xh A male with the XbY will have the recessive trait for baldness.

39. Polygenic • A trait that is produced (controlled) by two or more genes

40. Eye Color Example • Controlled by at least three genes. • Act together to produce your eye color

41. Lethal Genes • Any genetic trait that causes death. Examples: • Hemophilia- bleed to death • Huntington’s disease- brain shrinks

42. Lethal Genes Hemophilia (lethal and sex-linked) bleed to death XhY

43. Lethal Genes Huntington’s disease- brain shrinks