1. Sex linked inheritance

2. Human Genome
Autosomes
(1 – 22)
Sex Chromosomes
(X and Y)

3. X Y

4. SEX-LINKED RECESSIVE TRAITS

5. Haemophilia X-linked recessive inheritance
causes people to continue bleeding for a long time unless treated

6. Haemophilia

8. COLOUR BLINDNESS

9. Colour blindness: Alleles: X+ = normal vision, Xc = colour blind
(X+ is dominant)
phenotypes female genotypes male genotypes
normal X+ X+ X+ Y
colour blind Xc Xc Xc Y
carrier* X+ Xc
* carrier - transmits but does not express a trait

10. Carrier female Xc Xc X+Xc XcY X+ Y Female’s gametes Male’s gametes
Colorblind male X+
Male’s
gametes Y

11. Affected
individuals
female
male
carrier ?
Unknown
phenotype
progeny

12. GENERATIONS
Generations are numbered w/Roman numerals. Within each generation, individuals are numbered from oldest to youngest.

13. Baldness

14. Fragile X Syndrome
Fragile X syndrome (or Marker X syndrome ) is a genetic condition involving changes in the long arm of the X chromosome. It is characterized by mental retardation.