DNA (deoxyribonucleic acid) is the genetic blueprint that determines a person's biological characteristics. DNA is located in every nucleated cell of the human body. Upon conception, a child inherits half of his DNA from his mother and the other half from his father. Because DNA is passed down from the mother and father to a child, DNA identification provides a conclusive way to determine biological relationships.
Paternity analysis is based on a very simple principle: for any genetic system, an individual must obtain one gene from his mother and one gene from his father.

In our laboratory we extract and analyse the DNA to study certain regions by means of a very sophisticated technique known as the Polymerase Chain Reaction or PCR. These regions are known as genetic markers, microsatellites or STRs.

These genetic markers are known DNA regions with high variety between one person and another (they are very polymorphic). The different inherited forms are called alleles. The reasons why they are so valuable in genetic identification studies are:

1. Each person has genetic markers that differ from the rest, has his own alleles.
2. These genetic markers are inherited without changes and half of them will be identical to his father's and the other half will be identical to his mother's. A child will have two alleles for each genetic marker: one inherited from his father and the other, from his mother.

We use the selected sequences obtained by PCR to obtain the person's allele information by means of automatic DNA sequencing.

The analysis of the siblings alleles will provide us information on which one is inherited from the father and which one is inherited from the mother. From the comparison we can see that:

1. The alleged biological father has not been able to give some genetic markers present in the child. In other words: the child presents certain alleles that are no present in the father's DNA sample. In this case, biological paternity of the child is excluded.
2. The alleged biological father has been able to give the genetic markers present in the child. In other words: at least half of the alleles found in the child's DNA are present in the father's DNA sample. In this case, we will proceed with a complex statistical study to confirm the alleged father really being the biological father.

At ADF TecnoGen we analyse 15 genetic markers; this lets us reach a probability of paternity of over 99.999 %, when the mother is tested, and over 99.9 % when the mother isn't tested. These probabilities let us guarantee an absolute security on our results.

- Advice: the information in this section only refers to the techniques used by ADF TecnoGen. -