1. The Xs and Ys of Genetics
Sex Linked Genes
The Xs and Ys of Genetics

2. Sex Linked Genes
There are 23 pairs of chromosomes and one of those pairs are the sex chromosomes.
There are either X chromosomes or Y chromosomes.

3. Sex Linked Genes
These chromosomes not only carry the genes that determine male and female traits, but also those for some other characteristics as well.
Genes that are carried by either sex chromosome (X or Y) are said to be SEX LINKED or X-LINKED

4. Males Men normally have an X and a Y combination of sex chromosomes.
Since only men inherit the Y chromosome, they are the only ones that inherit Y-linked traits.

6. Females
Women have 2 X chromosomes

8. X Linked Traits
Men and Women can get the X-linked traits since both inherit X chromosomes.

10. Sex inheritance patterns for male and female children

11. X Chromosome Traits Men only have one X chromosome
Therefore genes on that chromosome are expressed in the male phenotype, even if it is a recessive gene.

13. X-linked traits
In humans, at least 120 genes are known to be X-linked.
Genes for hemophilia, red-green color blindness, congenital night blindness, and Duchene muscular dystrophy

14. Hemophilia An X-linked genetically inherited recessive disease
Can not clot their blood
Severe bleeding from minor cuts
Mostly in males

16. Red-Green Color Blindness
X-linked
Cannot perceive red and green in the same
Most often afflicts males