Loci is the plural term of locus. In genetic testing, analysts analyze a number of genetic loci on the DNA. In laboratories that have ISO 17025 accreditation will examine 21 loci; laboratories that are not ISO accredited will analyze a smaller number. The greater the number of loci tested, the more reliable your DNA test is. Genetic loci contain functional genes which are found on chromosomes. Functional genes are genes which are active.

The genes taken under examination are not random genes but very specific. The human body contains tens of thousands of genes and scientists are still not sure about the exact number. The DNA test would normally involve comparison of the genetic markers or loci between people to establish whether there is a biological relationship. Paternity testing will establish paternity only if the comparison of all 20 loci between the alleged father’s DNA profile and that of the child are the same. If the loci do not match then there is no biological relationship.

For more information about the results of a paternity test and how to read you’re results you can click here.