What are sex-linked traits? Chapter 3.9 What are sex-linked traits?

Inherited traits X and Y chromosomes carry genes (X chromosomes carry many genes, while Y chromosome carry few genes; thus the shape). Traits that are on these sex chromosomes are called ______________.

Sex-linked disorders Some diseases are on ______ chromosomes. For example: hemophilia and colorblindness are sex-linked disorders. ________________is a disorder in which a person the blood does not clot properly. ________________ is a disorder in which a person cannot see the difference between certain colors.

Hemophilia Hemophilia- a person with hemophilia does not have a special protein that helps blood to clot. It can lead to bleeding, bruising, and even death. The famous hemophiliac was Queen Victoria of England.

Hemophilia

Colorblindness- these people can’t see numbers below

Sex-linked disorders Sex-linked chromosomes are found more often in men than in women. It’s because of the gene being ____________.

Punnett Square for colorblindness XC Y XCXC (normal) XCY Xc XCXc XcY (colorblind) XC= normal Xc= colorblind Y =normal

Carriers A woman who has one normal gene and the one sex-linked gene is called a ________. That woman appears to be normal. She still, however, can pass the gene for it to children. All carriers have the heterozygous gene ex. XCXc, XAYa.

Pedigrees _______________– chart that shows inheritance of certain traits over several generations. It’s like a family tree. Pedigree helps to see who has a disease and who is a carrier.

Pedigree

Checking concepts: What are sex-linked traits?

Why does a female with a gene for sex-linked disorder usually appear normal?

Why do more men have sex-linked disorders?

Why can’t a male be a carrier for hemophilia?

How can a female have the sex-linked disorder of hemophilia?

What kind of gene-pair in the female carrier of a sex-linked disorder?

What is the purpose of a pedigree?

Fill in blanks: Traits that are inherited along with gender are called ___________ traits. Most of the genes for sex-linked traits are found on the ____________ chromosome. The genes for most sex-linked disorders are ____________. A female who has a gene for a sex-linked disorder but does not show the disorder is a ______________. A male who has a normal Y chromosome and an X chromosome for a sex-linked disorder _____________ have the disorder.