Genetics Disorders, Karyotypes, Pedigrees and Sex-Linked Traits Vocabulary

circle with full shading

female with recessive trait

square with half shading

male carrier; means the pedigree CANNOT be sex-linked

allele

Different forms of a gene

Phenotype

An organism's physical appearance, or visible traits.

Genotype

genetic makeup of an organism

Recessive

An allele that is masked when a dominant allele is present

dominant

An allele that is always expressed when present

Heterozygous

An organism that has two different alleles for a trait

Homozygous

An organism that has two identical alleles for a trait

carrier

Someone who has one recessive allele for a trait but doesn't show it.

Hemophilia

An X-linked recessive disorder in which blood fails to clot properly, leading to excessive bleeding if injured.

Down Syndrome

a genetic disorder of mild to severe intellectual disability and associated physical disorders caused by an extra copy of chromosome 21

color blindness

A sex-linked trait in which an individual cannot perceive certain colors.

circle with no shading

normal female

genetic disorder

An abnormal condition that a person inherits through genes or chromosomes

Karyotype

A picture of all the chromosomes in a cell arranged in pairs

Pedigree

A chart or "family tree" that tracks which members of a family have a particular trait

horizontal line between circle and square

a marriage

vertical line from the horizontal line between two parents

shows the offspring on a pedigree

square on the far right, of 3 siblings in a pedigree

youngest sibling (male)

Female Chromosomes

two X chromosomes

Male Chromosomes

one X and one Y

mutation

A change in a gene or chromosome.

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

Adenine always pairs with

Thymine

Thymine always pairs with

Adenine

Guanine always pairs with

Cytosine

Cytosine always pairs with

Guanine