1. Sex-linked Traits and Pedigrees
Biology
Genetics

2. Pedigree
Chart that shows how a trait and the genes that control it are inherited within a family.
Helps to determine the inheritance of some alleles and predict them in the offspring.

4. Pedigree video

5. Sex-Linked Traits
Genetic linkage that has to do with X and Y chromosomes.
Men = XY; therefore can inherit X or Y linked traits.
Female = XX; therefore can only inherit X linked traits.

6. Sex-linked Traits Men have only one X chromosome.
When an X-linked trait is inherited it will most likely be expressed in his phenotype because in most cases, there is no corresponding gene on the Y chromosome.

7. Sex-Linked Traits
Women: A recessive allele on one X chromosome is often masked in their phenotype by a dominant normal allele on the other chromosome.
This is why women are frequently carriers of X-linked traits but more rarely have them expressed in their phenotypes.

8. Inheritance of sex-linked traits video

9. Examples of Sex-Linked Traits
Hemophilia: Low levels or complete absence of a blood protein essential for clotting.
Was known as the Royal Disease carried by Great Britain’s Queen Victoria.

10. Examples of Sex-Linked Traits
Color Blindness: Color blindness (color vision deficiency) is a condition in which certain colors cannot be distinguished, and is most commonly due to an inherited condition. Red/Green color blindness is by far the most common form, about 99%, and causes problems in distinguishing reds and greens.

11. Are you Color Blind?

16. Autosomal vs. Sex
Autosomal Chromosomes: Refers to any of the chromosomes other than the sex-determining chromosomes (i.e., the X and Y) or the genes on these chromosomes.