NATURE VERSUS NURTURE

I was always wondering how someone's genes can affect his or her behaviour and health. On one hand you often see the same desease affecting generations in the same family, or you often notice children resembling their parents not only in looks but in behaviour as well. On the other hand you often see the opposite results. When I was in school, had a classmate whose both parents were alcoholics but who would never drink even at the party even when everyone around him would derink and have fun. He was always an A student even though he often was unable to study or to even simply stay at home. He would sometimes come to my place, would do his homework and would help me to do mine too. Later, he went on to study at a university, graduated, got married and became very successful in both his personal and his professional life. Judging from his background I don't think anyone would ever predicted it.

I recently did some reading and just as I thought, there are 2 theories on what affects human behaviour; nurture and nature. Nurture means that behavior depends on our experiences in life. Nature means that we are born with traits that later form our behavior. For example, many scientists believe that an extra Y chromosome causes aggressive behavior. Science also shows that genetics plays a role in things like obesity and addiction to smoking. A gene correlated with depression has also been discovered. Not that long ago, a Princeton molecular biologist published research in which he inserted a gene in brain cells associated with memory. After that, the experimental animals performed better in learning, and the press called this gene "the smart gene" and the "IQ gene," as if better memory was the best thing for defining intelligence. What the press didn't mention was that the learning improvements seen in this study were only lasting a few hours or a few days in some cases.

I am of course not a scientist, but I don't believe genes can always predict future health. Genes and behavior may both be needed for a person to be overweight, or to be addictive to smoking. From what I've read, there is no single gene that determines a particular behavior. Behaviors are complex traits involving multiple genes that are affected by many other factors. This fact is often overlooked in the press selebrating achievments in gene science, and, unfortunately, this can be very misleading. I think with deseases, behaviors, or any physical traits, genes are just a part of the picture, because many genetic and environmental factors involved in development of any trait. And having a particular genetic variant doesn't necessarily mean that a particular trait will develop. In fact, other factors may be keeping a gene from being turned "on".

The relationship between genes and behaviour is a more complicated issue than the connection between genes and diseases. Can our genes really make us act in a certain way? It looks like many ethical, and legal implications can be raised by this question. I think this relationship can be well summarized by a someone's statement I saw while doing this research: “all of our behaviours (and those of animals) are gene-dependent, but no behaviour is gene-determined”