Testing alleged father and child

In order to determine paternity we need to have samples of the alleged father and the child. Once we have the samples we use a type of biochemical technology called polymerase chain reaction (PCR) in order to extract the genetic blueprints and then compare these side by side.

Parents pass on half of their genes to their offspring – all contained in 23 chromosome pairs (a baby’s genetic code is 46 chromosomes; 23 inherited from the mother and the other 23 from the father). In a DNA test, we compare certain genetic markers between the tested father and child to see if they do share their genetic make-up, thus confirming that the alleged father is in fact the biological father.

About your actual test result

Laboratories are recognised by ISO 17025 (international standard for testing laboratory quality systems). We also offer different DNA paternity tests which you can choose according to your needs. Our home paternity test is simply there for peace of mind. We also offer our tests for legal purposes or immigration purposes.  Every test involves a complete evaluation between the genetic markers of two or more parties, thoroughly examining the number of shared genetic markers– to be exact – 21 genetic markers.

EasyDNA always recommends including the mother’s sample as this can help us increase the probability of paternity and give you an even more accurate result.  We do however, carry out many of our tests without the mother. We refer to paternity tests done without the mother’s samples as ‘motherless’.

The first possible type of result is an inclusion; this tells us that the father tested is the biological father of the child (paternity inclusion). The probability of paternity in this case is of 99.99%.

Another possible result is when the alleged father is not the biological father (exclusion of paternity). In this case, the probability of paternity (referred to as POP) will be of 0%.

Once we receive your DNA test samples in the laboratories and the 21 genetic markers are extracted, we then represent these in a table where each marker is listed – you will see these markers and the table in your paternity report. There are two columns; one column for the alleged father, one for the child and a third one may be included if the mother’s sample has been analysed.

Although we state 21 genetic markers, we actually test 20. The 21st genetic marker (sometimes called at genetic loci) is known as the amelogenin sex gene. This gene is one of the many genes that determine gender. We test this gene just to make sure our clients have not made an error when packing their samples or mislabelled them (they would, for example, place the father swabs in the envelope which reserved for the swabs of the mother)

What is the CPI?

There is a complex statistical analysis carried out in a paternity test. When we say the probability of paternity is 99.99% for example, we mean that the tested man is 99.99% more likely to be the biological father than another man chosen at random from his same ethnic group. The CPI, or combined paternity index, is a calculation that helps us arrive at the probability of paternity.

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