In genetic testing, the term genetic locus is important. Normally, a number of loci are taken under examination. A locus is a fixed position on a chromosome which contains a functional/ active gene. The human body has several thousand genes and although the human genome is known, the exact number of genes is still debatable ranging somewhere between 40,000 and 70,000 genes. In DNA testing, the number of loci examined is important as this will determine the accuracy of results. Companies boasting an ISO accreditation will use a total of 21 loci, though other laboratories may choose to do less. DNA testing will compare the same loci and genes between potentially related to people to establish whether they are genetically related. In a paternity test, an inclusion will means that all 20 loci tested on the father’s DNA can be found on the child’s DNA as well.