Genetic Terms

Easy explanations of key genetic testing terms.

DNA & Basic Terms

Short Tandem Repeat

STR

A specific gene region where 2-7 short base sequences are repeatedly arranged in the DNA sequence.

Allele

Allele

Genes that exist at the same position (locus) on a pair of homologous chromosomes and are involved in one trait.

Inheritance Patterns

Dominant Inheritance

Dominant Inheritance

When a disease gene is present on only one of a pair of homologous chromosomes, it acts dominantly over normal genes.

Recessive Inheritance

Recessive Inheritance

Disease occurs only when both chromosomes carry the disease gene.