The Amelogenin Sex Gene in Dna Paternity Testing

DNA testing is now the most widely used method for determining the biological relationships between individuals. The DNA paternity test is probably the most widely known of these tests and involves the testing of an alleged father, mother and the child in question. This test can also be conducted just between Alleged Father and a child without the Mothers sample.

When performing the Paternity Test, most DNA testing laboratories will test a minimum of 16 genetic markers for enhanced accuracy levels in excess of 99.99%. One of these genes tested is called the ‘Amelogenin’ gene and its use is to determine the sex of the sample that has been processed. Therefore in reality the statistical analysis is actually based on the matching of 15 of these 16 markers.

From a biological perspective, males have an XY chromosome and females have an XX chromosome. Therefore in your DNA test result you should see an XY for the alleged father and the child if he is male, and XX for the Mother and child if she is female. A DNA paternity test result from any serious service provider should report this gene together with the rest of the genetic markers analysed.

Functions and Uses of Testing the Amelogenin Gene

The testing of this gene may appear superfluous to a client at first instance, however it does serve a number of functions.

1. From a laboratory perspective, it acts as a primary quality control check and ensures that the correct samples have been processed. So for example, if the Alleged Father’s sample turns out to be female, then there is an element of quality control to identify the possible reasons. These could include problems such as the client putting the wrong samples in the wrong envelopes (e.g. putting the father’s sample in the mother’s envelope and vice versa). The testing of this gene can also act as a deterrent for submitting someone else’s samples (having said that, this applies only if the sample of someone of the opposite sex is supplied).

2. Gender identification through DNA testing has also got applications in the field of forensic DNA testing as it provides primary information regarding samples found at the scene of the crime during a criminal investigation. Through the test, it is possible to confirm whether biological remains found at the crime scene belong to males or females. It is also possible to differentiate this even in cases of mixed samples.

3. Gender identification is also applicable in the case of infidelity DNA testing. Analysis of the samples will show whether suspicious stains belong to a male or female individual. On the basis of this result, decisions for further testing can be based.

However, gender identification by amplification of the amelogenin gene can sometimes generate a result in which male samples were falsely identified as females. I have myself only seen few of these cases over the years. This occurrence is therefore very rare and occurs in less than 0.01% of cases in males and even less in females according to some studies. In such cases, it is suggested to perform the Y amplification of SRY gene or/and Y-STR markers to confirm the gender