DNA Technology
A DNA identity test, such as a DNA profile or a paternity test, is based on the simple fact that each individual’s DNA is unique, and it is inherited half from the biological father and half from the biological mother. Once a child is formed at conception, DNA does not change throughout a person’s lifetime.
Special locations (called loci) in human DNA have predictable inheritance patterns that could be used to determine biological relationships. These locations containing specific DNA sequences, called markers, are used for human identification. In a DNA paternity test, the markers used are Short Tandem Repeats (STRs), short pieces of DNA that occur in different repeat patterns among individuals.
Each person’s DNA contains two copies of these markers—one copy inherited from the father and one from the mother. Within a population, the markers at each person’s DNA location could differ in length and sometimes sequence, depending on the markers inherited from the parents. The combination of marker sizes found in each person represents his/her DNA (genetic) profile. This profile is unique for every person, and can be used to identify that person at any age.
In a paternity test, the report lists the genetic profiles of each tested party, noting the allele sizes of the different markers tested. If half of the child’s allele sizes match half of the allele sizes for the alleged father, it is called a genetic match, which means the alleged father is the biological father of the child. If there are non-matches, the alleged father can then be excluded from being the biological father of the tested child |
