Mutation (in DNA testing context) | DNA Testing Glossary
In DNA relationship testing, a mutation refers to a rare, spontaneous change in the number of repeats at an STR locus that occurs when DNA is passed from parent to child. This means a child may show an allele at a locus that differs by one repeat unit from what the biological parent actually carries. Mutations happen naturally and do not indicate a health problem. They occur at a known, low rate — roughly 0.1% to 0.3% per locus per generation. A single mutational mismatch at one locus does not result in an exclusion. Instead, the lab accounts for it by factoring the known mutation rate into the statistical calculations. An exclusion requires mismatches at three or more loci, which distinguishes a true non-match from a mutation event.
Related Terms
Allele, Locus, Exclusion, Combined Paternity Index, STR (Short Tandem Repeat)
