The human body consists of trillions of cells. Most of these cells have a nucleus, or center. The nucleus contains genes, the functional units of our heredity. The genes are grouped into separate bundles called chromosomes. We have 46 chromosomes inside every cell in our body. Twenty-three of these chromosomes came from our biological mother and 23 came from our biological father.
DNA Identification is the most precise and definitive method available for determining parentage. Everyone is born with a unique genetic blueprint known as DNA (DeoxyriboNucleic Acid.) Because DNA is passed down from mother and father to child, DNA Identification provides a conclusive way to determine biological relationships. Consequently, DNA typing has become the most accepted method within the legal and child support enforcement communities.
How does the test work? The test is based upon the principals of inheritance. A child gets one half of his/her genetic makeup from the mother and the other half from the biological father. The test reveals a control batch of genetic markers from all parties. The genetic markers that the child shares with the mother are first located. Then to determine paternity, the child's remaining markers are compared to the alleged father. If the man is indeed the biological father, all of the markers that did not match the mother's, should match his. If all of the child's remaining markers match the alleged father, evidence is provided that he is the biological father of the child.
A child receives half of its genetic profile from each parent. In the example below, under child, in the left column, it shows the Maternal Allele which is a piece of DNA passed on from the mother. The right column of the child shows the Paternal Allele which was inherited from the father.
When the mother is not tested, a larger batch of control markers is revealed from the alleged father and child. If these markers show that the man is contributing half of the genetic makeup of the child, he is given evidence that he is the biological father of the child. If markers are found not to match between the alleged father and child, the man is excluded from being the biological father of the child.
Probably the most common reason for DNA tests is to establish paternity by testing a mother, child and man thought to be the biological father. Because properly used DNA tests are so conclusive, paternity disputes can often be resolved without costly courtroom hearings. With the results of appropriate and timely DNA tests, lawyers are able to help clients resolve their paternity disputes in a more timely and less burdensome manner.
Even when the suspected biological father is not available, paternity can often be established using paternal relatives. If the man is deceased, for example, the presumed father's parents (or other relatives) could be used in his place. Depending on the situation, this might provide a valuable contribution toward obtaining social security for a minor child of a deceased man.
DNA testing can be used to indicate if two children have the same two parents, or if they only have one parent in common.
With the increasing use of assisted reproduction, DNA testing can be used to determine if the appropriate genetic donors were used.
It is sometimes necessary to establish a biological relationship for immigration purposes. For example, DNA tests can be used to establish (with a high degree of probability) a parent/child relationship between two people.
DNA testing may be the best way to distinguish between identical and fraternal twins. The identical twins would have exactly the same genetic patterns, while fraternal twins would differ in their patterns.
Determination of a biological relationship can play an important part in establishing connections between adoptees and biological family members, or separated family members. DNA tests may be able to make these connections.
For identification purposes, DNA fingerprints can be determined for individuals. DNA fingerprints can be used to develop a family tree for use in "genealogical studies".