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Dominant

Refers to an allele that masks the effect of a recessive allele paired with it in heterozygous individuals.

Genotype

The particular set of alleles that is carried by an individual's chromosomes

Heterozygous

Having two different alleles at the same locus on homologous chromosomes.

Homozygous

Having two identical alleles at the same locus on homologous chromosomes.

Locus

A particular location on a chromosome.

Phenotype

An individual's observable traits

Recessive

Refers to an allele with an effect that is masked by a dominant allele on the homologous chromosome.

Law of Segregation

A diploid cell has two copies of every gene that occurs on its homologous chromosomes. Two alleles at any locus are distributed into separate gametes during meiosis.

Law of Independent Assortment

During meiosis, alleles at one gene locus on homologous chromosomes tend to be distributed into gametes independently of alleles at other loci.

Codominance

Effect in which the full and separate phenotypic effects of two alleles are apparent in heterozygous individuals.

Incomplete Dominance

Inheritance pattern in which one allele is not fully dominant over another, so the heterozygous phenotype is an intermediate blend between the two homozygous phenotypes.

Multiple Allele System

Gene for which three or more alleles persist in a population at relatively high frequency.

Epistasis

form of gene interaction where alleles of one gene mask or conceal the allele of another.

Alleles

Forms of a gene with slightly different DNA sequences; may encode different versions of the gene's product.

Hybrid

Heterozygous individual.

Pedigree

Chart of family connections that shows the appearance of a phenotype through generations.

Polygenic Inheritance

when multiple genes are involved in the phenotypic expression of a single trait; usually results in a phenotypic spectrum

Purebred

Offspring from true breeding, having same phenotypes as parents.