DNA Testing Information and Resources

DNA Testing – Mistakes Can Happen!

admin — Sat, 22 Jan 2011 01:18:20 +0000

Although the results of DNA tests are reputed to be extremely accurate, there are certain problems that can, and do sometimes arise. In fact, because there are DNA testing issues and problems, it is very important to get an objective analysis of any DNA evidence, to make sure that no problems do arise.

One of the most common problems that can arise in DNA testing is a DNA mixture. This is when one or more people have contributed to a sample and three or more alleles are likely to be seen in at least one of the loci that are tested. These mixtures can be confusing and are sometimes subject to a few interpretations.

DNA testing issues and problems can also arise from degradation. When a sample is too old or exposed to harsh conditions, it can degrade – this can many times be useful information for defendants in a court case. When degradation occurs, the amplicon size increases, causing peak heights to fall progressively. Determining peak height imbalances becomes difficult to interpret, due to loss of peak height information. Allelic dropout also occurs in degraded samples.

Stutter peaks also cause DNA testing issues and problems. These stutter peaks are found in nearly every electropherogram and are small peaks that happen either immediately before or after a real peak. In DNA testing, there is a process known as the PCR amplification process. In the PCR amplification process, the polymerase can lose its place when copying a strand of DNA, and normally slips forwards or backwards four base pairs. This means that, instead of the real fragment being amplified, there is a small amount of DNA fragment copies that are either one repeat smaller or larger.

Peak height imbalance can also cause DNA testing issues and problems. These imbalances are calculated in heterozygous loci (they contain two alleles). If the difference in the height of the two peaks is greater than 30% it is generally considered that a peak height imbalance has occurred. Taking into consideration that a sample from one person should contain peaks that are almost equivalent in height, an imbalance of peaks means that the sample is a mixture.

Sometimes, a blob of dye appearing on the electropherogram output tends to show up as a wide shape, and can cover a true allele. Air bubbles, sample contamination, and urea crystals can also be the cause of large peaks that can cover the contributions made by different contributors or can even be mistaken as contributions made by either a victim or a suspect.

Pull-up, sometimes known as bleed-through, spikes, or EPT data problems, and raw data problems, are more DNA testing problems and issues that have to be dealt with efficiently in order to avoid potential adverse DNA testing results.

How to Choose DNA Testing Providers

admin — Sat, 15 Jan 2011 01:16:24 +0000

The issues for which DNA testing is employed are weighty, complex issues which have the potential to change a person’s life forever. These are issues that pertain to paternity, crime, and a whole range of medico-legal issues.

It is highly imperative that samples are obtained accurately, the procedure carried out with accuracy and near-zero room for error so that the outcome can be a just and fair one and reflective of the true state of affairs as far as the issue under adjudication is concerned. Choosing the right DNA testing providers is imperative.

So how do you choose a DNA testing provider? Some of these tips will help you make a great choice.

DNA testing is a complicated process that must be performed by qualified and highly experienced scientists who adhere to strict laboratory standards. Take the interpretation of the test results for instance. It is possible to obtain a false positive or a false negative report.

In a false positive (inclusion) result, a paternity test may result in a false inclusion (give the result that the tested man is the father even though he is not). This would obviously create a very nasty situation, especially is a repeat test invalidates this result. A DNA test provider who gives a 99% inclusion result is also saying that statistically, 1 in every 100 mails will give the same result. These days, it is standard for a DNA test provider to aim to achieve figures that are closer to 100; 99.99% for example. This can be achieved by testing at least 16 and even up to 24 different DNA marker points, which increases the statistical accuracy of the result.

A false negative (exclusion) result is one in which the tested man is not considered to be the biological father. False negatives typically occur due to sample mix-ups or sample contamination in the lab. A DNA test provider should be able to practice dual testing, where the sample is divided into two and the same test performed on the samples independently by two teams, and final results compared to see if they match. Use of automated processors to collate and process samples in order to eliminate sample mix-ups is a hallmark of a good DNA test provider.

Generally speaking, when selecting a DNA testing facility:

Be sure it is accredited and certification is up to date.
Consider a facility which practices double testing to increase the accuracy of results.
Choose a lab with an experienced staff to ensure accurate results.
Understand that the actual number of genes tested directly impacts the results.
It will also be a good idea to choose a DNA test provider that will offer extensive counseling, especially in the area of determining paternity. It is amazing how many people think so little of this aspect until a result comes up to shake the very foundations on which a home or family is built.

It is also important that when it comes to DNA testing, cheap does not necessarily mean the best. It is better to pay more to get an accurate result, than to use a cheaper option that may not guarantee accuracy in results.

Ethnicity Testing

admin — Sat, 08 Jan 2011 01:14:35 +0000

In the last few years, more and more African Americans have been undergoing ethnicity DNA tests to determine their African ancestry. This is not just limited to African Americans. In many heterogenous societies, people have more than ever before started to wonder where their ancestries are traceable to. Many adopted children would love to know who their original parents are, as well as their places of origin.

These and other questions are being answered through the use of ethnicity testing techniques, thanks to modern advances in DNA testing technology. In ethnicity testing, DNA samples are collected using the buccal swab technique, and the DNA results matched against the existing ethnic profiles that have been compiled from studies such as the Human Genome Project.

There are three variations of ethnicity testing:

ETHNIC DNA TESTING TYPE #1: Y-DNA Testing of Your Paternal Line

This test assesses the extent of paternal ancestry based on the Y-chromosome (the male chromosome). It assigns specific paternal haplogroups to specific nationalities. This is measured in percentages. For example, 30% of American and Caribbean blacks have a European haplogroup because many of their great-grand parents who worked on plantation farms as slaves were fathered by the plantation owners, who were mostly European settlers to America.

This type of genetic testing also identifies genetic cousins. Since this test is based on the Y-chromosome, it can only be taken by males.

ETHNIC DNA TESTING #2: Mitochondrial DNA Testing of Your Maternal Line

This is based on the fact that mothers pass on their mitochondrial DNA to her children (male and female). So it is used to trace the maternal lineage. Results are typically ready in four to six weeks.

These two tests are based on the sex chromosomes.

ETHNIC DNA TESTING #3: Autosomal DNA Testing

This uses 22 out of the 23 human chromosome pairs to measure total ancestry composition. These 22 pairs of chromosomes come from both paternal (22) and maternal (22) lines. The basic assumption is that certain marker values occur at different frequencies in different populations. By comparing the individual’s results with that of specific population groups, ethnic groups or world regions where the individual’s total combination of ancestry is most common can be identified.

A typical test result will include the following items:
1. A certificate with a results table showing your ancestral proportions.
2. A graphical representation of your results.
3. Your genotypes at tested markers.
4. A user manual explaining the results.

Sibling Testing

admin — Thu, 30 Dec 2010 01:11:48 +0000

Sibling DNA testing is used to determine whether the two people in question share the same biological parents, especially when those parents are not available for testing. Sibling testing can determine if the test subjects are full siblings or half siblings.

Full siblings are individuals who are born of both biological parents. Half siblings share only one biological parent, either the mother or the father.

Sibling analysis is not as conclusive as paternity testing. The results will provide a statistical likelihood of whether two individuals are true biological relatives, but sibling analysis cannot provide a conclusive result. The statistical likelihood in this case is expressed as a likelihood ratio. The likelihood ratio summarizes the information generated from the DNA test. A likelihood ratio of LESS than one means that the test subjects are unlikely to be related. A likelihood ratio GREATER than one means it is likely that the test subjects are related. (The range is from one to infinity)

If any of the parents of the siblings who are being assessed are available for testing, this will increase the certainty of the result. As in a paternity test a DNA profile is produced for each person made up of a number of DNA markers. The DNA profiles of the two people are then compared.

On average full siblings will share more DNA markers than half siblings, and half siblings share more DNA markers than unrelated people. The statistical analysis performed will determine the most likely relationship given the DNA results.

There are different variations of sibling testing.

BROTHERS Y-TEST

This is premised on the fact that all men have one Y chromosome which they pass to all their sons. By testing this Y chromsome in two or more brothers, we can see if they have the same father. The results of sibling testing for males is 99.9%.

SISTERS X-TEST

The basis of this test stems from the fact that all men have one X chromosome which they pass to all their daughters. By testing the X chromosome in two sisters, it is possible to detect if the test subjects have the same father. This test is best carried out for sisters with different mothers.

MITOCHONDRIAL TEST

Mitochondrial DNA is only inherited from the mother, so it is the ideal test to see if siblings have the same biological mother. The accuracy of the test is highly dependent on the type of mitochondrial DNA you have. If two matching persons have a rare type of Mitochondrial DNA then they are more likely to be siblings, than two persons who match with a common type of mitochondrial DNA.

The full sibling test is required to test a brother and sister for the same father.

Hair Paternity Testing

admin — Thu, 23 Dec 2010 01:09:04 +0000

Testing of samples of the hair has become an important tool in paternity DNA testing. In many cases where the paternity of an unborn child is in question, it is not uncommon to see many alleged fathers refusing to submit themselves for testing using the conventional buccal swab technique. Since consent must be sought from all parties before medical procedures are carried out, hair paternity testing has become one of the so-called “discreet/forensic testing” methods. This is also important when pregnancy has resulted from sexual abuse or sexual assault, and in cases of retroactive testing when the subjects are dead or missing.

Hair paternity testing can therefore be defined as the process of determining the paternity of an unborn child using hair samples from the alleged father, while using other conventionally collected samples from the mother and foetus.

In all cases, hair samples used for hair paternity testing must be complete with the hair follicle or root attached so as to obtain a more complete DNA profile. Cut hair does not have a significant amount of DNA.

Many murder and rape cases have been solved by using hair paternity testing, especially if there was a struggle and the hair of the assailant was pulled on and got lodged in the woman’s nails.

Generally, 6-10 strands of hair are required to build a complete DNA profile for a hair paternity DNA test. Hair paternity test results are usually admissible in court if a legal battle ensues.

A Prenatal Paternity Test Will Prove The Identity Of The Biological Father!

admin — Thu, 16 Dec 2010 01:03:50 +0000

A prenatal paternity test is done when it is necessary to prove whether a man is the biological father of a child. This test is carried out on the unborn child when those involved do not wish to wait until the child is born to determine paternity.

A trained physician will take prenatal samples using well-established methods. DNA is then extracted from these samples and analysed. Because DNA is formed at conception and never changes, the same conclusive results will be obtained with a prenatal paternity test, as with a normal paternity test.

If the test is to be for personal knowledge only, samples from the alleged father as well as the mother can be collected using a home kit. However, if the testing is required in a legal situation, then it needs to be done following the legal channels. Documentation processes have to be followed, that are acceptable by the courts as well as other government agencies, to determine and prove in a court of law, whether the alleged person is the father of the baby or not.

DNA prenatal paternity testing gives a probability of 99.9% or higher of paternity, and 100% probability that the alleged person is not the father of the child. In a prenatal paternity test, the prenatal sample, as well as the mother and alleged father are tested. The mother needs to be involved in this test because the laboratory undertaking the testing needs to distinguish her DNA from that of the baby’s in the prenatal sample that contains cells from both the baby and the mother.

Prenatal samples are collected by following one of two procedures, depending on the stage of the pregnancy. The first, chorionic villi sampling, or CVS, is done during the 10th to 13th weeks of pregnancy. This involves taking a small sample from the placenta, the membrane that partially surrounds the developing fetus, either by way of the vagina, or through the abdominal wall.

Then there is the amniocentesis test, which can be carried out during the 14th to 24th weeks of pregnancy. A sample of amniotic fluid is drawn from the sac surrounding the developing fetus. This amniotic fluid contains fetal cells that are used in analysing the DNA. Amniotic fluid is obtained by inserting a needle through the abdominal wall.

Both these procedures are invasive, with a slight risk of infection, and an even smaller risk of miscarriage, and are only carried out by a trained physician. These procedures are also both used to determine any genetic birth defects or other possible health problems with the baby.

These prenatal paternity tests are the only accurate tests that are available, and although somewhat expensive, are the only options available for those wanting or needing a paternity test carried out. If the amniocentesis test is carried out for medical purposes, there are insurance companies that may cover the fee involved.

A Father Paternity Test – Genetic Proof Whether You Are The Father Or Not!

admin — Thu, 09 Dec 2010 01:00:51 +0000

Although older methods are still used in parental testing, DNA is at the moment the most advanced and accurate way to determine parentage. A father paternity test done in this way will give genetic proof whether a man is the biological father of a baby or not. With DNA testing, proof that the alleged father is not biologically related to the baby will be 0%, and 99.9% will be definite proof that the alleged father is indeed biologically related to the baby.

Many times, when it is suspected that a woman may have had an affair, doubts arise as to the paternity of her child. In order to clarify whether her partner/husband is indeed the biological father of her child, a father paternity test will be carried out. This test is carried out to make sure that the biological father of the child will accept and carry out his responsibilities as a father.

There are standard, cheaper, father paternity tests available, the results of which are for your own private knowledge. However, should the test be required as evidence in a court of law, a laboratory member of the AABB Parentage Testing Accreditation Program has to carry out the actual testing for the procedure to be considered legal.

The reason for this is first of all to ensure that the tests are done properly, that legal channels are followed, and that documentation processes are done properly and are acceptable in a court of law. In other words, proper records of the outcome of the father paternity test are essential, as with any other type of legal situation.

Having a father paternity test has its advantages and its disadvantages as well. If found that the boyfriend/husband is the father of the child, then this will get rid of any suspicions of the woman in the relationship/marriage having an affair. However, it will also cause resentment on the part of the woman, as she will realize, and not like the fact, that her partner/husband did not fully trust her.

Of course this means that because of the father paternity test, regardless of the outcome, the relationship or marriage could suffer adversely, and in many cases, even end. It is for this reason that a father paternity test should initially be carried out privately, the results only being known to you and your husband/partner. In the event of the relationship/marriage ending, a legal paternity test can be carried out.

A father paternity test can and will save a lot of unnecessary conflict, as it will give conclusive proof whether you are the biological father or not. Also, as the DNA of an original egg cell will be in your genes for the rest of your life, a father paternity test can be carried out on anyone, from a fetus to an adult.

Pre Paternity Test – Best Way To Determine The Identity Of The Father

admin — Mon, 29 Nov 2010 00:57:09 +0000

Under certain circumstances it becomes necessary to do pre-paternity testing to determine the father of the child. These tests are available, but are not available as home testing kits. Pre-paternity testing has to be carried out by a trained physician.

While it may be necessary for the mother to want or need to know the identity of the father of the child, the life and health of the unborn fetus is of utmost importance to the doctor. The procedures that are available for pre-paternity testing are sometimes slightly invasive when taking some of the DNA in order to determine the identity of the father. Although the test is not harmful to the baby in most cases, it does involve the fetus being disturbed, and there are certain factors that need to be considered.

When considering pre-paternity testing, it is very important that the doctor examine the mother to see how far she is into the pregnancy in order to determine what type of re-natal paternity testing can be carried out. The doctor will also check the health of both the baby and the mother, to determine whether complications are a possibility or not. If the doctor has any doubts whatsoever, he/she will recommend that the pre-paternity testing be carried out after the birth of the baby.

There are two extraction methods that the doctor can carry out in order to obtain the DNA necessary for the test. The first method is CVS, or chorionic villi sampling, that can be performed during the tenth and thirteenth weeks of pregnancy. A sample of the placenta can be obtained either through the vagina or the abdominal area. This will give conclusive identity of the father, as the material that makes up the placenta has exactly the same DNA as the original egg cell.

Between the fourteenth and twenty-fourth weeks of pregnancy, an amniocentesis test can be carried out. A needle is inserted into the amniotic sac and a small amount of the fluid extracted. As this test is done directly into where the fetus is developing, there are risks involved, although complications from this test are very rare.

Although both methods pose a risk for the mother and the baby, both are safe in most cases. There is always concern that the needle may injure the baby during the amniocentesis test, but because doctors are now well trained in this method, the risks are a lot less than when the procedure was first introduced. Bleeding and cramping could also occur with both of these methods, however, staying in contact with the doctor will ensure that nothing goes wrong.

Due to the invasiveness of both procedures, and laboratory fees involved with extracting the DNA from the samples, pre-paternity testing is expensive. If an amniocentesis test is done to determine the health of the baby, there are some insurance companies that will cover this test, although not for paternity testing.

Free Paternity Test

admin — Thu, 01 Apr 2010 22:43:09 +0000

Are you in fear of not being able to afford a paternity test? If this is the case, there is nothing to worry about. There are free paternity tests available to help you find out who the real father of your child is.

Why Is A Free Paternity Test Offered?

One reason why there are free tests such as this is that there are a lot of young expectant mothers. If these mothers are not yet established, they will not be able to shoulder the costs of the tests.

Another reason why these tests are free is if they will be used as evidence in court. Due to the legal nature of the need, various companies are contracted to administer these tests to ensure they are not tampered with. This is another reason why these tests are free.

What Is A Paternity Test?

A paternity test is done to accurately determine is a child was fathered by a particular man. This is done through DNA comparison. Through DNA testing, the paternity of a man cannot be denied. It is the most accurate method of finding out if a man is the biological father of a child or not.

There are two types of free tests. These tests are done after the child is born, and the results can quickly be processed.

Here are those 2 tests:

Blood Test

A blood test involves collecting a small sample of blood from the child. With just a small sample of blood, the biological father can be accurately determined.

Buccal Swab

A buccal swab is another free paternity test. Unlike a blood test that requires the collection of blood, with this test, all that has to be done is to enter a sponge or Dacron tipped swab into the child’s mouth. The swab is then rubbed against the inner cheek to collect DNA samples.

The Purpose Of These Tests

There are a lot of purposes behind these tests. Aside from knowing the paternity of a child, there are other medical purposes. One purpose is to find out if the child has any genetic defects. Through this test, it will be known if the child suffers from any abnormalities, which helps its parents prepare.

These tests are also used for legal purposes. In court, these tests are administered to determine if a man is a child’s father or not. In this way, the man cannot deny the child’s financial support and future.

Advantages

When it comes to medicine, parents will know if their unborn child is normal, or if the child has defects. It helps them prepare mentally, and prepare for what lies ahead. In worse case scenarios, a free paternity test helps parents decide whether they want to keep the child or not.

When legal matters are concerned, these tests give men no choice but to support their child. It also gives fathers the right for visitation rights, if the mothers deny the men of their paternal rights.

In any case, free paternity test is the most uncontested method of finding out if a man is the father of a child or not.

Paternity Test Before Birth

admin — Tue, 23 Mar 2010 11:55:05 +0000

With the rising numbers of children growing up without or not knowing their own fathers, there is a great need for a paternity test before birth. Often times, men deny that they have fathered the child, and women often do not know how to prove it. Thanks to advancements in medicine, these pre-natal paternity tests are readily available.

How Are These Tests Administered?

There are actually two ways to go about these tests. Both tests involve minor surgery that involves minimal risks. These tests have the ability to determine who the father is, through DNA testing. These test can also determine if the child is normal or not, which allows parents to prepare for the future.

Here are those methods:

Chorionic Villus Sampling (CVS)

This test can be administered 10 to 13 weeks after the woman’s last period. This test involves invasive surgery to both mother and child, since the child is still inside the womb. A sample of the placental tissue or CVS is gathered for DNA testing.

Amniocentesis

This test can be administered 14 to 16 weeks after the woman’s last period. This test involves inserting a needle into the mother that collects amniotic fluid. This fluid is found in the amniotic sac, which surrounds the developing fetus. This fluid contains fetal tissue that contains the baby’s DNA.

What Are The Risks?

There are a few risks that a paternity test before birth has that you should know about. Just like any medical procedure, there are risks involved. These risks include cramping, bleeding, and harm to the child inside the womb. This is why you should make sure that a trained and reputable professional is administering the procedure.

What Is The Purpose Of These Tests

There are a growing number of children abandoned by their fathers even before they are born. This leaves the mothers no choice, but to shoulder the financial support that was supposed to be shouldered by both parents. To avoid this from happening, the test determines who the father is. This prevents the father from denying the unborn child his responsibilities.

Initially, these tests were administered to determine through DNA testing, if the unborn child have any genetic abnormalities. In some cases, the pregnancy poses risks to both mother and child. A paternity test before birth enables the parents to take the necessary action to ensure both the child and mother’s safety.

What Are The Advantages?

Before these men can run away from their responsibilities, a paternity test before birth will enable the woman to take legal action, and get the child support that she needs. This prevents the possibility of financial strain to the expectant mother, and ensures a better future for the unborn child. This also lessens the stress of the expectant mother. We all know how stress can affect the development of the unborn child.

In any case, these tests will make sure that mother and child are in perfect health. A paternity test before birth also ensures that a father does not run away from his responsibilities.