DNA is passed on by your parents and is responsible for your individuality. Each of us is made up of 23 pairs of chromosomes. We are the result of combination of a single egg and a single sperm cell....these cells go through a dividing process changing from 23 chromosomal pairs to 23 chromosomes.


DNA (deoxyribonucleic Acid) is the genetic material that makes us who we are

Your personality, your habits, your features, your likes, your dislikes etc. are all determined by your genetic blueprint. It is found in almost every cell of your body and it controls everything that you do and everything that you are.

DNA is passed on from your parents. It is responsible for your individuality and also keeps you connected to your biological family.

How does that happen? How can you share family traits and not be identical to them? The answer is in how you came to be.

Each of us is made up of 23 pairs of chromosomes. We are the result of the fusion of a single egg cell and a single sperm cell. When the body creates egg or sperm cells, these cells go through a dividing process that takes them from 23 chromosomal pairs to just 23 chromosomes (one of each). An egg cell has 1 copy of chromosome 1, 1 copy of chromosome 2 and one copy of each chromosome right up to 23. This is not enough to create a human. It is not until the egg is fertilized with a sperm cell that a human embryo is formed. The sperm cell brings with it, it's own copy of each of the 23 chromosomes. Once fertilized, the egg cell contains everything that it needs to create a new human being.

This means that exactly half of our DNA comes from our mother and half from our father. It is this, that allows paternity testing to be possible.

A laboratory will look at 16 specific areas of each individual DNA sample. These areas are called loci (locus- singular). Since we all have 2 copies of each chromosome, the lab will have two readings for each locus tested. The reading is in the form of a number.

The numbers of the DNA loci are compared once testing is completed. For an individual’s locus, one number must match one of the mother's numbers for that locus. The child's other number will match the biological father's.

A paternity index is then calculated. The paternity index is a calculation of how often that match occurs in a particular race population. It is the likelihood that the tested man is the biological father of the tested child based on that locus. But 1 locus is not enough to conclusively determine paternity. That is why 16 different loci are tested.

Each locus has its own paternity index. If all the loci match, the paternity index for each is combined and a probability of paternity is calculated. The probability of paternity is the final percentage calculated.
If the tested man does not match the tested child on a locus, the paternity index is zero for that locus. If there are 4 or more non-matches the probability of paternity is 0%.