Ch. 10.5: Sex-Linked TraitsGenes located on the X or Y chromosome

XX = Female; XY = MaleObjectives:

1. Explain how sex-linked genes produce different inheritance patterns in males and females.

2. Explain why most sex-linked disorders are more common in males.

Vocab: sex-linked gene

X vs. YMore genes on X

Male karyotype Female karyotypeX: more than just genes for sex traits.

Thomas Hunt Morgan & Fruit FliesDiscovers sex-linked traits.

Recessive white eyes more common in MALE fruit flies.

Females have to be homozygous recessive to have white eyes. Males only need one recessive allele for trait.

Sex-linked genes affect MALES more than females.

Females can be carriers XNXn

Males will express trait with just one allele, XnY.

Females have to be homozygous recessive to express trait.

Sex-Linked Disorders Color-blindness Hemophelia Baldness Fragile X Versions of Muscular Dystrophy

These are recessive disorders.• There are dominant disorders that are more prevalent in

females.

Color-blindness

Hemophelia

Prevents blood clots.

Without clotting factors (proteins), you can bleed to death.