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

Want to Live an Extra 10 Years?

Prenatal Paternity Testing Is Important

Of course there are many different versions of the science of dna testing that have been helping people for years, but at the same time there are always a few versions that find more use in the public arena than most.

Take paternity testing for example. Now this is the science that has been around for long enough now that there has been a certain trust built up with the public over the procedures and facilities where they go to have these tests done. One of the procedures that can actually determine the biological relationship between a man and a child can be accomplished before the child is even born.

Paternity Testing Before Birth

While there are different names for it, paternity testing before birth or prenatal paternity testing is a necessary and important part of the process. Still, while the biological relationship between the man and a child is the most form of this test, there are other reasons for this version of paternity testing.

Technological Advancements

The other advancements in technology have made it so that it’s not always clear if the woman carrying a child is the biological mother. With the new advancements in technologies where eggs and sperm are donated, the implications of prenatal paternity testing can take on a whole new dimension.

Facilities

Of course you’ll need to make sure that the facility where any of these dna testing procedures are carried out is the best in that it should be accredited and run by professionals. You’ll need to make sure that any of the places where you might go to have any one of these paternity testing procedures carried out has the staff that can carry out the sample collections in a reasonable manner as well.

One of the other things that should help you to make your decision are the locations that the place you’re considering has. Remember that the most professional of these companies will have the most locations to serve you and all these places should be staffed by trained professionals that know all about the things that make the collection process both safe and comfortable.

Remember too that you will want to have your privacy respected and to that end you’ll want to find a place that has a policy in effect so that the results of a court ordered paternity test or some other form are not made public against your wishes.

Want to Live an Extra 10 Years?

Paternity Testing on Absent Fathers

DNA testing is one of the most conclusive ways available to determine paternity of any given child. By taking a sample of DNA from both the alleged father and from the child in question, high-tech DNA profiling techniques are used to match reference points across genetic markers on both samples which can lead to an accurate determination of where a genetic relationship exists.

In an ideal world, paternity testing would have available both a sample from the child and from his alleged father in order to best establish the link between them. However, in some DNA paternity testing cases the father is not available to give his DNA sample, whether through choice, or unavailability for some other reason. However, where the father is absent, it is still possible to use other DNA tests to determine whether a relationship exists.

DNA Testing on Other Direct Relatives

By performing DNA testing with other members of the family that share some of the same genes with the alleged father, it is possible to determine whether or not there is a likelihood of paternity over the child in question. Obviously the father’s sample is desired for reasons of accuracy and conclusivity, however it is more than possible (particularly with advancing testing technologies) to be able to determine paternity through shared genetic material through more distant relatives to the father. In other words, provided a relative of the alleged father is available for DNA testing, you should be able to obtain some results although this may not always be conclusive.

DNA Testing on Grandparents

In the absence of the alleged father or any separate sample of his DNA, the alleged paternal grandparents can provide the key to establishing paternity. By taking a sample from either one or both the grandmother and grandfather of the baby, it is possible to determine even in the absence of the father whether or not there is shared genetic material and consequently whether or not there is a shared relationship, i.e. parentage.

DNA Testing on Male Relatives

Y-STR testing is one of the most innovative DNA testing methods honed in recent years, tracking down the male-only Y- chromosome to establish genetic links between male children and elder vertical male relatives, for example grandfathers, great grandfathers, even great uncles by blood relationships. This can be particularly handy where the father is unavailable and direct elderly relatives have died, given that a great deal of genetic material passes unmutated from father to son throughout generations. Of course, this is however absolutely of no use for DNA testing of female children.

DNA Testing on Siblings

Alternatively siblings can also provide a close genetic match, which makes it possible to test whether or not two children are related by the whole blood, rather than half. Where there is dispute over the potential father of a child, an alleged sibling’s sample can be a good way to compare DNA to determine the extent of the relationship. The same can be said for brothers and sisters of the alleged father, who can also share some genetic material sufficient to provide a result in DNA testing of the child in question,

If your situation requires is such that you require to do the DNA testing through one of the alternatives above, it is always advisable to contact in advance the company who will be performing the DNA test and explain your case in full so that they can advise you on the DNA testing options available as well the results that can be obtained.

Want to Live an Extra 10 Years?

Five Top Things to Know About a Dna Paternity Test

Whilst the awareness about DNA Paternity testing has greatly increased throughout most of the world, there is still a lot of information about the test that is not known.

The following are the five top things to know about a DNA Paternity Test:

1. Most accurate method of determining biological relationships

A DNA Paternity test is the most accurate way of determining a biological relationship between an alleged father/mother and their child. Whilst in the past blood grouping analysis was used as a screening method, the relevance of this test has been greatly reduced as the level of accuracy of this type of test is low compared to the result of a DNA test. A DNA paternity test will provide 100% certainty of exclusion and 99.9%+ probability of inclusion.

2. Difference between an At-Home Paternity Test and a Legal Paternity Test

The difference between an At-Home Paternity Test (also called Curiosity Test) and a Legal Paternity Test is not the actual result but the way in which the sample collection is performed. For an At-Home Paternity test, a home dna kit is normally sent to the requesting party. The kit will normally include i) oral swabs to take the saliva sample, ii) documentation to provide relevant information including consent iii) instructions and terms and conditions of sale. The sample is taken by the parties themselves who are participating in the test. In a Legal DNA Paternity Test, the sample collection must follow a strict chain of custody procedure. All samples need to be collected and documented by a independent third party (normally a qualified general practitioner or nurse) who will be responsible to verify and authenticate the samples. The actual result of the paternity in terms of the biological relationship will not differ.

3. Always select a properly accredited laboratory

Always chose to do your paternity test through a company that uses an ISO17025 and/or AABB accredited laboratory. This will ensure the quality and accuracy of the results. Also make sure that when report the result a full DNA profile is provided for the 16 loci analysed, as well as the statistical probability of paternity. A simple Yes/No answer should not be deemed acceptable.

4. Paternity tests can be performed without the sample of the mother

To perform a DNA Paternity test the sample of the Mother is not necessary to obtain an accurate result. However, when available, it is always recommended that the sample of the Mother is also provided. Only in specific cases will the sample of the mother provide more accurate results such in the case of gene mutation. Many companies offer to test the mother at no extra charge.

5. DNA can be obtained from a diverse range of samples

It is possible to obtain DNA from a number of other sources such as hair, blood, semen and items such as cigarette butts and a toothbrush. Whilst the current standard is to use an oral swab to collect saliva samples, in cases where a person may not be physically present, able or willing to donate a sample, then alternate samples can be obtained.

Want to Live an Extra 10 Years?

Dna Paternity Testing: Submitting Non-standard Samples (part 2)

Success Rates for DNA Extraction from Non-Standard Samples

In part 1 of the article, we looked at some of the more common non-standard samples used to obtain DNA from an individual for DNA testing purposes. In this article we look at DNA extraction success rates from the various types of samples and how these can vary from one sample to another.

Non standard samples do not always guarantee that a DNA Profile will be obtained. Whilst for buccal swabs it is possible not to obtain DNA, such as in cases where the swabbing was not adequately performed or else the swabs grows mould due to damp storage conditions, in general problems with this type of sample are normally less than 2%. Therefore depending on the nature of the sample, there is usually associated a High, Medium or Low probability of success in extracting DNA from each type of sample (in some cases a percentage probability of success is provided).

High (80%) : For samples such as fresh blood stains or hairs with root where, for a qualified and experienced DNA laboratory, extracting DNA is considered relatively straightforward. In such cases, as long as the sample is handled properly both during collection and delivery to the laboratory, one can expect a high probability of success in extracting DNA.

Medium (50%-60%) : For samples such as a toothbrush or cigarette butts the success rate is influenced by a number of variables including heavy use vs light use and/or storage conditions etc. Therefore a heavily smoked cigarette butt found in an ashtray at home is more likely to result in a successful DNA extraction than a lightly smoked cigarette that has been thrown on the street and exposed to the elements (e.g. rain).

Low (20% – 30%) For samples such as teeth or bone, where extracting DNA is a relatively difficult and time consuming process, these normally need to be handled by a highly specialised laboratory. In such cases, the individual should consult the laboratory first to check their level of expertise, if they will accept the sample and the cost.

The classification above is however only a guideline, since as we have seen it is not just the type of sample that is important but also other variables can have an influence such as :

1. Poor storage conditions (e.g. damp environment, extreme heat etc)

2. Poor sample handling (possible contamination with other DNA or dirt by touching the sample)

3. Not enough DNA present (e.g. heavily used toothbrush vs used once only)

It is also important to note that the success rate will also depend heavily on the ability of the laboratory performing the test. Not all laboratories that can perform DNA Paternity testing on normal swabs are capable of obtaining DNA from a wide variety of other media. The more difficult the media (e.g. teeth and bone), the greater the specialisation and experience required to increase the chance of a successful DNA extraction.

Finally, it is also important to note that with non-standard samples there is always a risk that the extraction will not work. Therefore any person considering submitting such a sample, especially where it may be only a limited sample available (e.g. person is dead), should take this into consideration. Selection of an experienced laboratory (possibly of forensic specialization) will help minimize this risk.

Want to Live an Extra 10 Years?