Sex-Linkage and Recombination

SEX CHROMOSOMES

organism’s biological sex.

2 x chromosomes

how many x chromosome does a female have

one x and one y chromosomes

how many x chromosome does a male have

RECOMBINATION

a process by which pieces of DNA

are broken and recombined to

produce new combinations of

alleles

CROSSING OVER

exchange of DNA between paired

homologous chromosomes (one from each

parent) that occurs during the development

of egg and sperm cells (meiosis).

Chiasmata

site of crossing over

Sex-Linked Traits

refers to characteristics or traits

that are influenced by genes

carried on the sex chromosomes.

AFFECTED

an individual who expresses a certain trait or characteristic

UNAFFECTED

an individual who is completely normal in reference to a trait

CARRIER

an individual who does not express the trait but carries the

allele that codes for the trait (applicable to females)

COLORBLINDNESS

 Inability to see colors in a normal way.

HEMOPHILIA

a bleeding disorder in which a person

lacks or has low levels of certain

“clotting factors” and the blood doesn’t

clot properly as a result, leading to

excessive bleeding.

HYPOPHOSPHATEMIC

RICKETS

characterized by impaired

mineralization of bones due to

low levels of phosphate in the

blood.