GENES AND BEHAVIOR

By Roland Watson

I concluded the last article by commenting that human behavior is shaped by a number of different factors. The first of these is genetics: our collection of different genes.

What are genes?

This begs the question, what are genes?

Genes are chemical units called molecules. They are collections of atoms of the different naturally occurring elements.

More precisely, they are electro-chemical units. All atoms have electrons, and atoms combine by forming what are called valence bonds, which is the sharing of electrons. It is the combined atoms that constitute molecules.

Genes are also systems or forms, in the sense that they do something. They have a purpose.

Our cells, every one of them, every skin cell, hair cell, you name it, contain 23 pairs of what are called chromosomes, which in turn are comprised of DNA.

Actually, there is an exception to this, since sex cells - sperm and egg cells - contain only one copy of each chromosome.

DNA is a very long string of chemicals, somewhat like a ladder, and which spirals. The rails are composed of one set of chemicals, and the steps of combinations of four other chemicals. Sections of the ladder that have a specific function, and which can be inherited from one generation to the next, are individual genes.

I should add, we also have some genes in another structure inside our cells, called RNA. But, for DNA, the 23 pairs of chromosome ladders have from tens of millions to over 200 million steps each, and which "code" hundreds to thousands of individual genes.

We now understand that we have about 20,000 genes. This number is down from old estimates of 80,000 to 100,000. To me, this doesn't seem like that many, when you think about everything that is going on with a person.

Genetic DNA and "Junk" DNA

The steps in the ladders that are not part of our inheritable genes used to be considered "junk DNA." They are formally called Noncoding DNA, because they don't code the protein sequences that constitute genes.

Scientists now realize that the noncoding sequences aren't junk at all. They have important roles regulating the behavior of the sequences that are genes.

The subject of this talk is supposed to be genes and behavior, so how does that work? Indeed, scientists traditionally did not assign any behavioral impact to genes. How can chemicals inside our cells shape what we do?

The mechanical system

We need to think of the body as a mechanical system. If one thing happens, this causes something else to happen, which in turn regularly causes something else to happen as well. And, these are real physical things.

A simple mechanical system is a light switch and a light. If you turn on the switch, this causes an action. It effectively opens a gate, and allows electricity to flow through the cord to the light. When the electricity reaches the light, another action occurs. The electricity is converted, by another system - the light bulb, into light.

The physical actions inside the body are chemical - chemical reactions. The body is an extremely complex mechanical system, of countless chemical reactions.

What I want to stress is that there is nothing mysterious or supernatural about this. It is just an extremely complicated set of reactions, and although we understand many of them, we still have a long way to go to get the complete picture.

Our genes, which are chemicals, are "expressed" - they create other chemicals, which in turn react to form other chemicals, and so on and so on. From this a baby is born, and grows, and lives.

Chemical behavior

Our behavior is also chemical. When you do something, from a physical act such as raising your arm, to an emotional act like getting excited, these are also the consequences of chemical reactions inside your brain and body.

For non-physical behavior, including thought and emotion, there is still a very long way to go to understand all of the chemical steps that are involved, the mechanical systems that create what we think and feel.

In summary, genes are responsible for your appearance, including your sex; your skin, eye, and hair color; and your body type. Genes - genetic deficiencies - also underlie many different types of disabilities, which people are either born with, or which they develop over time.

For behavior, genes drive your instincts, your overall level of intelligence and particular aptitudes, many other specific behavioral tendencies, and even your basic character or personality.

Behavioral DNA

For example, one gene has been found to play a key role in the production of the neurotransmitter chemical, dopamine. When dopamine is present in large quantities, this is is linked to excitable, fickle, thrill seeking, and quick-tempered character traits.

Derived from this, there is research that shows that your choice of a political party may also have genetic links.

As another example, the gene that creates a protein called NR2B, plays a critical role in learning. This protein is involved in the production of brain cell switches called NMDA receptors, which enable the brain to fire the neural networks that represent "associations," such as of a face and a name.

Indeed, genes have numerous impacts on intelligence, or the various characteristics of what is considered to be intelligence, and hence through it on our behavior as well.

A basic area of genetic research is to identify all of the potential roles that genes may have, including both physical and behavioral. For behavior, many, many new links are being revealed.

Consequences

It is also important to recognize that while some genetic consequences are written in stone, others are not. The effects of genes can further be grouped like this:

Genetic programming is responsible for our physical characteristics - at least at birth, and such programming necessarily is manifested.

Some genetic programming, though, leads only to predispositions, and additional factors are required for the characteristics to be manifested.

One example of this is the predisposition to contract a particular disease, such as occurs with some women and breast cancer. But, by regulating their behavior, these women can reduce the odds that they will get the disease.

Finally, certain behavioral traits are also genetically predisposed, but their manifestation can be counteracted as well. For instance, for people whose brains produce a lot of dopamine, the exercise of self-control can offset the predisposition to have a quick temper.

A basic point in these articles is that if you have genetically-linked behavioral traits that you would prefer not to have, you don't have to be stuck with them. You can work to counter them, and be the person that you want to be.

In the next article, I will examine the impact of social conditioning on our behavior.