2.2.3 PBS Vocab

Genotype

An organism's genetic makeup, or allele combinations.

Phenotype

An organism's physical appearance, or visible traits.

Alleles

alternative versions of a gene

dominant allele

An allele whose trait always shows up in the organism when the allele is present.

recessive allele

An allele that is masked when a dominant allele is present

Homozygous

An organism that has two identical alleles for a trait (HH/hh)

heterozygous

An organism that has two different alleles for a trait, one dominant and one recessive (Hh)

Pedigree

A diagram that shows the occurrence of a genetic trait in several generations of a family.

autosome

Any chromosome that is not a sex chromosome

sex chromosomes

X and Y chromosomes.

autosomal dominant

inheritance pattern of a dominant allele on an autosome; like NF1 or FH

autosomal recessive

two copies of an abnormal gene must be present in order for the disease or trait to develop; like sickle cell anemia

Punnett Square

A chart that shows all the possible combinations of alleles that can result from a genetic cross