Sunday, 21 April 2013

Can epigenetics merge the nature/nurture debate

Can epigenetics merge the nature/nurture debate, Ever since the mapping of the genome, scientists have discovered the answers to many questions related to behavior, psychology, aging, disease, etc. An increasing amount of data that is coming back from various genome studies is exponentially turning out more findings.

These findings are making it easier to isolate certain genes for certain traits. Yet despite these findings it is becoming more evident that the expression of the gene is only half the story.

The other half is how the gene is sequenced. These findings may help answer problems that are becoming more pressing for society as a whole. Subjects related to healthcare costs, mental health, side effects of prescription drugs, and stringent laws regarding selling of unhealthy food.

The easy answer to these questions is found in the relationship to ‘nature and nurture’, a debate that has been going on between people since the age of enlightenment. Up to now the debate has been isolated to academia and bar rooms conversations.

This is simply because the ‘nature’ side of the argument is based in science and objective reasoning, where the ‘nurture’ side deals with nuance and subjectivity. But ever since the sequencing of the genome, researchers are discovering through epigenetics that the line between nature /nurture is becoming more and more dulled.

What is epigenetics?

Epigenetics, which is essentially a way for nature to explain the way nurture works, literally means “above the gene”. What that means is that scientists have discovered that how genes are packaged will reflect their expression. Because every gene in your genome has the exact same DNA sequencing, it relies on something called methyl groups to give it instructions on how each cell should ‘behave’.

For example, a cell in your eye has the same DNA sequencing as a cell in your toe, but the instructions given lets an eye cell be an eye cell. (*) But some methyl groups can be misplaced and redirect the sequencing process, which in turn alters that genes expression.

Similarly, histones and cromatin, which are proteins responsible for 'wrapping' of DNA. DNA is wrapped tightly into what is known as a nucleosome. Research has shown that stressors in a genetic lineage can effect the expression of that gene for subsequent generations.

In particular a study that involved laboratory mice and a gene called agouti, which is phenotypically expressed in weight gain, with hair color serving as an indicator that the gene has been turned off. Mice who had a yellowish tint to their hair did express the gene and inevitably became obese.

This obesity in turn greatly increased the chances of disease. But what was disturbing from the study was that offspring of the agouti trait were more likely to be born with that trait even if their mothers did not eat the methyl rich foods. That is because not only is the DNA is inheritable, but the way the gene is wrapped, stored and expressed also is.

Of course what is passed down doesn't necessarily have to be negative, what epigenetics does is pass down genetic 'ghost'. For instance if your great grandparents survived a drought, you may have inherited a gene to deal with long periods of malnourishment.

So what do fat mice and the Russian Famine of 1921 mean to us today? Well, the more researchers discover about how the mechanism for gene expression works, and how tags that control our genes can change the closer they can get to altering the cells causing abnormal triggering which can lead to diseases like cancer, diabetes, etc..

Further discoveries in this field can help us not only find a way to slow down or cure terminal diseases, but also help in finding each persons genetic 'fingerprint'. The more information doctors have about each persons specific traits and how to work with them, then the more likely it will become that broad brush prescription drugs with dozens of side effects will be substituted for patient specific treatment.

Also earlier detection of traits like obesity and diabetes can help the catastrophic effects of late treatment. These effects are being felt not only on the patients, but the consumer and the astronomical cost of healthcare.

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