1. What is sex linkage?
Males have the genotype XY whereas females are XX.
Create a genetic diagram to show the possible genotypes produced.
What are the phenotype ratios.

2. What is sex linkage? Objectives Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the inheritance of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

3. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

4. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

5. Sex linkage
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

6. Sex linkage
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

8. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

9. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

11. What is sex linkage? Task
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Task
Complete the questions on sex linked conditions
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

12. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

13. Sex-linked genetic crosses
Red-green colourblindness:
Let XB = chromosome with the allele for normal vision
Let Xb = chromosome with the allele for colour blindness
Y = chromosome with no gene for vision
Parents phenotype Normal mother x Colour blind father
genotype XB XB Xb Y
Gametes
♀\♂ Xb Y XB
XBXb
XB Y
Offspring genotypes: XBXb XBY
Offspring phenotypes: Female carrier Male normal

14. Haemophilia ♀\♂ XH Y XHXH XH Y Xh XHXh Xh Y
Let XH = chromosome with the allele for normal blood clotting
Let Xh = chromosome with the allele for haemophilia
Y = chromosome with no gene for blood clotting
Parents phenotype Carrier mother x Normal father
genotype XH Xh XH Y
Gametes
♀\♂ XH Y
XHXH
XH Y Xh
XHXh
Xh Y
Offspring genotypes: XHXH XHXh XHY XhY
Offspring phenotypes: Female Female Male Male
normal carrier normal haemophilia

15. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

16. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

17. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

18. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

19. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.

20. What is sex linkage?
Outcomes
3: Describe sex linkage and some associated conditions
5: Explain fully how sex linked conditions can be inherited.
7: Evaluate the role of the X and Y chromosomes in the transfer of named examples of inherited conditions.
Key terms: sex linkage, haemophilia, colour blindness, inheritances.