Genes located on the X chromosomes (some cause diseases)

The Y is much smaller, contains few genes

Sex Linked Disorders
Color Blindness (red-green)
Hemophilia ("bleeders disease)
Duchenne Muscular Dystrophy (weakening/loss of skeletal muscles)

Crosses Involving Sex - Linked Genes

**remember the Y is wimpy, no genes go there **

Consider the Hemophilia - this disease is caused by an allele on the X chromosome