Unit 5 intro to genetics

Gene

a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring. A section of DNA that codes for a protein

trait, characteristic

any factor used to describe or distinguish

Variation

Any difference between individuals of the same species.

Allele

An alternative form of a gene.

Genotype

genetic makeup of an organism

Phenotype

An organism's physical appearance, or visible traits.

Homozygous

An organism that has two identical alleles for a trait

Heterozygous

An organism that has two different alleles for a trait

Monohybrid

A cross between individuals that involves ONE pair of contrasting traits

Dihybrid

a hybrid that is heterozygous for alleles of TWO different genes.

Dominant

Describes a trait that covers over, or dominates, another form of that trait.

Recessive

An allele that is masked when a dominant allele is present

Chromosomes

threadlike structures made of DNA molecules that contain the genes

Centromere

Area where the chromatids of a chromosome are attached

Telomere

repetitive DNA at the end of a eukaryotic chromosome

Chromatid

one half of a duplicated chromosome