Why test the amelogenin gene in a paternity DNA test?

DNA testing technology is now a highly advanced sector and constantly improving and making new discoveries. For anyone seeking to know who the biological father of a child is, then theDNA paternity test is by far the most precise and scientific means of doing so. The test will involve a number of genetic markers and amongst these is a gene known as the amelogenin sex gene which is found in both males and females.

Genetic markers in DNA paternity testing

A DNA Paternity Test relies on the close examination of very specific locations on the long and tangled DNA molecule. These locations on the molecule are referred to as genetic markers and scientists in advanced laboratories usually analyse usually 24 on the DNA samples of the alleged father, the child and often the mother. Out of the 21 genetic markers tested, one is known as the amelogenin sex gene and simply helps determine the sex of person submitting that sample.  We may in fact say that the test relies on the statistical analysis of 20 rather than 21 genetic markers.

Sex and the gene

The amelogenin sex gene is found on both the male Y chromosome and the female X chromosome. It is one of the sex determining genes in humans. To bear in mind that females have a pair of XX chromosomes whilst males have a pair of XY chromosomes. Any DNA test result from a reputable company will make reference to these chromosomes in their results and further elaborate on the genetic profiles of the people involved in the test.

I shall refrain from using the term gender to refer to Male or female, but will rather use the term sex as this is more scientific. Gender is often viewed as a cultural construct rather than a biological state.

testing the amelogenin gene: why?

The following is amongst the reasons why testing this gene is important:

1. In infidelity DNA testing, testing this gene is important as it will determine whether the DNA found in a suspect stain sent to be tested belongs to a female or a male.
2. In forensic DNA testing, testing for the gene is also very useful. Imagine a crime scene in which the body found has decomposed and cannot be recognized by simply looking at it. For forensic experts and anyone involved in the investigation, it is crucial to know whether the remains are male or female- this can be done by testing for the amelogenin sex gene.
3. In paternity DNA testing, testing this gene ensures quality and companies that take DNA testing seriously, will test this gene. There may be cases where a father’s DNA samples might have been placed in the mother’s envelope or the mother’s sample might have been placed in the mother’s envelopes; this can be done by accident or deliberately. Samples can be clearly classified if this gene is tested and the error done by the client rectified. It moreover might deter anyone trying to tamper with results by stating that samples belong to a male when they in fact, belong to a female.

Problems when testing the amelogenin gene

The gene is found on both the Y chromosome in males and the X chromosome in females. In some cases, a deletion of the amelogenin gene on the Y chromosome will lead to analysts classifying male DNA as female DNA.  Further testing of other genetic markers on the Y chromosome will produce conclusive results and will avoid misclassification of the samples in such amelogenin abnormalities. However, the incidence rate of this deletion of the gene on the Y chromosome is as low as 0.001% and should not be of concern to anyone doing a paternity DNA test.