Over the years, the science of genetics has given us insights into our health and behavior. A recent study published in Nature Neuroscience suggests that experience of abuse during childhood can leave scars on the genetic make up that last for life.

A previous study in rats revealed that baby rats reared by negligent or indifferent mothers had increased the amount of methyl compounds on a region of DNA that regulates the expression of a receptor for glucocorticoid hormones. Glucocorticoids play an important role in metabolism and stress management. The neglected baby rats had fewer receptors for glucocorticoid hormones than normal, thus affecting the animals’ ability to handle stress.

In another study, researchers at Montreal’s McGill University analyzed brain samples from people who had committed suicide. The research study revealed that suicide victims with a history of child abuse had a methylation pattern similar to that previously observed in the neglected rat pups. In addition, they also had fewer glucocorticoid receptors compared to those without history of abuse.

The findings of the study suggests that experience of abuse as a child leaves scars on the DNA that may fact stress management later in life. Several studies demonstrated that childhood experiences can affect adult behavior. The Canadian study is the first to demonstrate that the effect of abuse can go far down to the genetic level.

A new product at your local pharmacy is selling like hotcakes. It`s the Home DNA Paternity Test from Identigene, a ?do-it-yourself? paternity test kit available over-the-counter.

Here`s how it works: Cell samples are collected from the inside of the cheeks using swabs provided in the kit. Cell samples from the father and from the child are collected separately. The samples are then mailed to an accredited lab where genetic tests are performed. Results are available by phone, online or by mail.

So far, so good.

Now comes the tricky parts, mainly dealing with the following questions:

• How accurate is the test?
• How will it stand up in a court of law?
• Who is buying such kits?
• What are the consequences of such a test?

Accuracy
The report comes back with a probability figure ? the likelihood of paternity. Identigene claims it ?routinely provides results probabilities greater than 99.99%?, thus providing conclusive proof of genetic relationship. However, self-collected samples are not foolproof. There is always the risk of contamination and fraud.

Legal issues
Some experts say there is no guarantee that such a test result will stand up in court. It may be admissible as evidence but the jury needs to be fully convinced of its accuracy for it to serve its purpose. There are, however, other such tests developed mainly for forensic purposes.

Users
Custody, inheritance, child support, divorce, or simple curiosity. These are just a few issues that push people to buy and use the test kit.

Consequences
Clearly, the test is meant for private purposes only. But the results can have far-reaching consequences. Broken relationships, broken homes, broken hearts ? these might be just a few negative consequences that such a test may bring. Though to be fair, something positive may also come out of it ? reunions, putting things right, getting justice, or just plain peace of mind.

The test is here. It is simply a man-made tool that we can use to answer questions. In the end, it`s our own decision and judgment that count.

Sources:

MSNBC 27 March 2008

Identigene

Just when I thought I know everything there is to know about identical twins, comes this new revelation. It seems that identical twins, previously thought to have 100% genetic resemblance, are anything but identical.

A group of researchers from the US, the Netherlands, and Sweden studied the genetic make up of 19 pairs of identical twins. They found that there are subtle but clear differences between the DNA of these twin pairs. These variations may be due to differences that occur during genetic copying and to mutations. In most cases, these slight differences have no observable effect in the physical and developmental make up of the twins. In some cases, however, these variations can make a world of difference health-wise. And we are not talking only about simple ailments but also serious and debilitating diseases as Parkinson`s and cancer.

Doctors were always puzzled how one twin can develop a disorder or disease and the other not. They`ve always attributed these differences to environmental factors. In the case of my twin boys, F developed eczema and asthma while R didn`t. And I`ve always asked myself, where did I do wrong? Have I somehow neglected one and favor the other? After all, I, the mom, am responsible for a lot of these so-called environmental factors, from food, to beds, to toys and baby products. It`s a relief to know that genetics, something beyond my control, plays a role in all of these.

But now, I`m at loss. With this new discovery, the the term ?identical twins? has become a misnomer. Monozygotic would be a more appropriate term but who would understand that? The next time somebody asks me whether my boys are identical, how do I respond?

Source:

Bruder et al., 2008. Phenotypically Concordant and Discordant Monozygotic Twins Display Different DNA Copy- Number-Variation Profiles,

The American Journal of Human Genetics (2008), doi:10.1016/j.ajhg.2007.12.011.