1. Multiple Alleles and Sex-Linked Patterns of Inheritance

2. Multiple alleles
a gene inheritance pattern in which at least three unique alleles are present for one trait
the three alleles may interact with each other using any other pattern (Dominant/Recessive, Incomplete Dominance, Codominance, etc.)
at least three phenotypes are possible

3. Multiple alleles
heterozygous individuals’ phenotypes must be determined using other inheritance patterns (Dominant/Recessive, Incomplete Dominance, Codominance, etc.)
Example in humans
ABO blood type in humans

4. Multiple Alleles & Codominance

5. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = __________, TB = __________, t = __________
TATA = __________, TAt = __________,
TBTB = __________, TBt = __________,
TATB = __________, tt = __________

6. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = __________, t = __________
TATA = __________, TAt = __________,
TBTB = __________, TBt = __________,
TATB = __________, tt = __________

7. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = __________
TATA = __________, TAt = __________,
TBTB = __________, TBt = __________,
TATB = __________, tt = __________

8. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = type O blood
TATA = __________, TAt = __________,
TBTB = __________, TBt = __________,
TATB = __________, tt = __________

9. Multiple alleles

10. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = type O blood
TATA = __________, TAt = __________,
TBTB = __________, TBt = __________,
TATB = __________, tt = __________

11. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = type O blood
TATA = type A blood, TAt = __________,
TBTB = __________, TBt = __________,
TATB = __________, tt = __________

12. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = type O blood
TATA = type A blood, TAt = type A blood,
TBTB = __________, TBt = __________,
TATB = __________, tt = __________

13. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = type O blood
TATA = type A blood, TAt = type A blood,
TBTB = type B blood, TBt = __________,
TATB = __________, tt = __________

14. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = type O blood
TATA = type A blood, TAt = type A blood,
TBTB = type B blood, TBt = type B blood,
TATB = __________, tt = __________

15. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = type O blood
TATA = type A blood, TAt = type A blood,
TBTB = type B blood, TBt = type B blood,
TATB = type AB blood, tt = __________

16. Multiple alleles
use capital and lowercase letters and/or superscript letters to show different alleles
TA = type A blood, TB = type B blood, t = type O blood
TATA = type A blood, TAt = type A blood,
TBTB = type B blood, TBt = type B blood,
TATB = type AB blood, tt = type O blood

17. Sex-linked
a gene inheritance pattern seen when a trait is determined by a gene found on one of the sex chromosomes
many traits are located only on the X chromosome
leads to many recessive characteristics being common in males
males only have one copy of the X chromosome

18. Sex-linked Examples in humans
colorblindness, hemophilia (bleeder’s disease)

19. Sex-linked
must use sex chromosomes as part of Punnett Square allele identification along with capital and lowercase letters and/or superscript letters to show different alleles
XN = X chromosome with a normal gene, Xn = X chromosome with a colorblind gene, Y = no gene
XNXN = _______________, XNXn = ________________, XnXn = _______________
XNY = _______________, XnY = _______________

20. Sex-linked
must use sex chromosomes as part of Punnett Square allele identification along with capital and lowercase letters and/or superscript letters to show different alleles
XN = X chromosome with a normal gene, Xn = X chromosome with a colorblind gene, Y = no gene
XNXN = normal female, XNXn = ________________, XnXn = _______________
XNY = _______________, XnY = _______________

21. Sex-linked
must use sex chromosomes as part of Punnett Square allele identification along with capital and lowercase letters and/or superscript letters to show different alleles
XN = X chromosome with a normal gene, Xn = X chromosome with a colorblind gene, Y = no gene
XNXN = normal female, XNXn = normal female, XnXn = _______________
XNY = _______________, XnY = _______________

22. Sex-linked
must use sex chromosomes as part of Punnett Square allele identification along with capital and lowercase letters and/or superscript letters to show different alleles
XN = X chromosome with a normal gene, Xn = X chromosome with a colorblind gene, Y = no gene
XNXN = normal female, XNXn = normal female, XnXn = colorblind female
XNY = _______________, XnY = _______________

23. Sex-linked
must use sex chromosomes as part of Punnett Square allele identification along with capital and lowercase letters and/or superscript letters to show different alleles
XN = X chromosome with a normal gene, Xn = X chromosome with a colorblind gene, Y = no gene
XNXN = normal female, XNXn = normal female, XnXn = colorblind female
XNY = normal male, XnY = _______________

24. Sex-linked
must use sex chromosomes as part of Punnett Square allele identification along with capital and lowercase letters and/or superscript letters to show different alleles
XN = X chromosome with a normal gene, Xn = X chromosome with a colorblind gene, Y = no gene
XNXN = normal female, XNXn = normal female, XnXn = colorblind female
XNY = normal male, XnY = colorblind male

25. There are multiple alleles for human blood type
There are multiple alleles for human blood type. The allele for blood type A (TA) is codominant with the allele for blood type B (TB) while the allele for blood type O is recessive (t). If a heterozygous type A blood woman marries a heterozygous type B blood man, what is the likely phenotypic ratio of their kids?
Identification of Alleles TA = type A blood TB = type B blood t = type O blood Parent Genotype Identification Woman: TAt Man: TBt

26. There are multiple alleles for human blood type
There are multiple alleles for human blood type. The allele for blood type A (TA) is codominant with the allele for blood type B (TB) while the allele for blood type O is recessive (t). If a heterozygous type A blood woman marries a heterozygous type B blood man, what is the likely phenotypic ratio of their kids?
Punnett Square TA t TB t

27. There are multiple alleles for human blood type
There are multiple alleles for human blood type. The allele for blood type A (TA) is codominant with the allele for blood type B (TB) while the allele for blood type O is recessive (t). If a heterozygous type A blood woman marries a heterozygous type B blood man, what is the likely phenotypic ratio of their kids?
Punnett Square TA t
TATB TB t

28. Punnett Square TATB TBt
There are multiple alleles for human blood type. The allele for blood type A (TA) is codominant with the allele for blood type B (TB) while the allele for blood type O is recessive (t). If a heterozygous type A blood woman marries a heterozygous type B blood man, what is the likely phenotypic ratio of their kids?
Punnett Square TA t
TATB
TBt TB t

29. Punnett Square TATB TBt TAt
There are multiple alleles for human blood type. The allele for blood type A (TA) is codominant with the allele for blood type B (TB) while the allele for blood type O is recessive (t). If a heterozygous type A blood woman marries a heterozygous type B blood man, what is the likely phenotypic ratio of their kids?
Punnett Square TA t
TATB
TBt
TAt TB t

30. Punnett Square TATB TBt TAt tt
There are multiple alleles for human blood type. The allele for blood type A (TA) is codominant with the allele for blood type B (TB) while the allele for blood type O is recessive (t). If a heterozygous type A blood woman marries a heterozygous type B blood man, what is the likely phenotypic ratio of their kids?
Punnett Square TA t
TATB
TBt
TAt tt TB t

31. There are multiple alleles for human blood type
There are multiple alleles for human blood type. The allele for blood type A (TA) is codominant with the allele for blood type B (TB) while the allele for blood type O is recessive (t). If a heterozygous type A blood woman marries a heterozygous type B blood man, what is the likely phenotypic ratio of their kids?
Phenotypic Ratio of Children 1 type AB blood : 1 type A blood : 1 type B blood : 1 type O blood

32. If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Identification of Alleles TA = type A blood TB = type B blood t = type O blood Parent Genotype Identification Woman: TA_?_ Man: TATB

33. If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Punnett Square TA ? TA TB

34. If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Punnett Square TA ?
TATA TA TB

35. If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Punnett Square TA ?
TATA TA TA TB

36. Punnett Square TATA TA TATB
If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Punnett Square TA ?
TATA TA
TATB TA TB

37. Punnett Square TATA TA TATB TB
If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Punnett Square TA ?
TATA TA
TATB TB TA TB

38. Where is the Type B child?

39. Punnett Square TATA TA TATB TB
If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Punnett Square TA ?
TATA TA
TATB TB TA TB

40. Punnett Square TATA TAt TATB TBt
If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Punnett Square TA t
TATA
TAt
TATB
TBt TA TB

41. If a child has Type B blood and his father has Type AB blood, what would his mother’s genotype be if her phenotype was Type A blood?
Mother’s Genotype TAt

42. In humans normal color vision is due to a dominant allele
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Identification of Alleles XN = normal vision Xn = color deficient vision Y = no gene Parent Genotype Identification Woman: XNXN Man: XnY

43. Punnett Square XN XN Xn Y
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Punnett Square XN XN Xn Y

44. XNXn Punnett Square XN XN Xn Y
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Punnett Square XN XN
XNXn Xn Y

45. XNXn Punnett Square XN XN Xn Y
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Punnett Square XN XN
XNXn Xn Y

46. XNXn Punnett Square XNY XN XN Xn Y
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Punnett Square XN XN
XNXn
XNY Xn Y

47. XNXn Punnett Square XNY XN XN Xn Y
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Punnett Square XN XN
XNXn
XNY Xn Y

48. In humans normal color vision is due to a dominant allele
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Color Deficient Daughter Probability 0/4 Color Deficient Son Probability

49. But are there really 4 daughters?

50. In humans normal color vision is due to a dominant allele
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Color Deficient Daughter Probability 0/4 0/2 Color Deficient Son Probability

51. Remember to simplify fractions!

52. In humans normal color vision is due to a dominant allele
In humans normal color vision is due to a dominant allele. Red-green color deficiency is due to its recessive allele. This gene is present on the X chromosome and thus is sex-linked. A homozygous normal female has children with a color deficient male. What is the probability that one of their daughters is color deficient? What is the probability that one of their sons is color deficient?
Color Deficient Daughter Probability 0/4 0/2 0 Color Deficient Son Probability

53. In humans hemophilia (bleeders disease), is due to a recessive X linked allele. The normal condition (your blood clots) is due to the dominant allele. Show the phenotypic ratios possible in a cross between a heterozygous female and a normal male.
Identification of Alleles XN = normal blood clotting Xn = hemophilia Y = no gene Parent Genotype Identification Woman: XNXn Man: XNY

54. In humans hemophilia (bleeders disease), is due to a recessive X linked allele. The normal condition (your blood clots) is due to the dominant allele. Show the phenotypic ratios possible in a cross between a heterozygous female and a normal male.
Punnett Square XN Xn XN Y

55. In humans hemophilia (bleeders disease), is due to a recessive X linked allele. The normal condition (your blood clots) is due to the dominant allele. Show the phenotypic ratios possible in a cross between a heterozygous female and a normal male.
Punnett Square XN Xn
XNXN XN Y

56. Punnett Square XNXN XNXn
In humans hemophilia (bleeders disease), is due to a recessive X linked allele. The normal condition (your blood clots) is due to the dominant allele. Show the phenotypic ratios possible in a cross between a heterozygous female and a normal male.
Punnett Square XN Xn
XNXN
XNXn XN Y

57. Punnett Square XNXN XNXn XNY
In humans hemophilia (bleeders disease), is due to a recessive X linked allele. The normal condition (your blood clots) is due to the dominant allele. Show the phenotypic ratios possible in a cross between a heterozygous female and a normal male.
Punnett Square XN Xn
XNXN
XNXn
XNY XN Y

58. Punnett Square XNXN XNXn XNY XnY
In humans hemophilia (bleeders disease), is due to a recessive X linked allele. The normal condition (your blood clots) is due to the dominant allele. Show the phenotypic ratios possible in a cross between a heterozygous female and a normal male.
Punnett Square XN Xn
XNXN
XNXn
XNY
XnY XN Y

59. (include differences for females and males)
In humans hemophilia (bleeders disease), is due to a recessive X linked allele. The normal condition (your blood clots) is due to the dominant allele. Show the phenotypic ratios possible in a cross between a heterozygous female and a normal male.
Phenotypic Ratios
(include differences for females and males)
2 normal females : 1 normal male : 1 hemophilic male