Sex determination and Sex-linked traits

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

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

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)

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