1. Sex determination and Sex-linked traits

2. Sex determination: the father. determines the sex of the child
Sex determination: the father determines the sex of the child P1 = XY x XX

3. Sex-linked traits: are on the X chromosome
EX: colorblindness
XY – normal male
XX – normal female
XcY – colorblind male
XcXc – colorblind female
XcX – carrier female

4. Why are there no carrier males
Why are there no carrier males? The trait is on the X and males have only one X (Men either have the trait or don’t) Why are men more likely than women to be colorblind? XY or XcY = 50% XX or XcX or XcXc = 33% (carriers have normal vision)

5. Ex: Hemophilia: the blood does not clot
P1 = XhY x XhXh