Gene-Environment Interaction

Our traits are basically divided into genetic and environmental. Genetic factors are the ones a person is born with, and a large chunk of these factors are inherited from the previous generations. Environmental factors include chemical, physical, nutritional, infectious and behavioural factors. Many prevailing diseases such as diabetes and cancer are caused by the complex interplay of genetic and environmental factors. Both the factors will play a part in influencing the diseases. Some may be more influenced by the genetic factors while others will be largely affected by the environmental factors. But, most of the diseases are always associated with the genetic makeup and many inherited diseases can be influenced by environmental conditions.

Some genetic effects are seen only in certain environmental conditions

If you have a genetic predisposition to antisocial behaviour, you may not demonstrate the trait until you experience abuse or neglect in your childhood. If you have had a stress-free and normal  childhood, you will never express this specific genetic trait. The expression of a specific trait towards which you are genetically predisposed  can be prevented by protective environmental factors. If you have a predisposition to alcohol abuse and live in an alcohol-prohibited environment, it may not express itself. Thus, protective genetic factors have a comparatively less significant  effect if environmental exposure is strong.

Few environmental effects are visible only under certain genetic conditions

Response to environmental exposure depends on the genotype, which is a term that defines your genetic make-up for a specific trait/disease. If you have had stress in your early life, it may cause depression in later years. This is only when certain genotypes are present. A person’s genotype can also determine their response to specific medications and their side-effects through various biochemical mechanisms. There is an entire branch of science that studies this called Pharmacogenomics.

Sometimes, genetic effects can influence your environment too

•         If you are an extrovert, you will prefer different social environments than introverts.
•         If you are a person who likes art and have artistic abilities, you will seek an environment that allows development and expression of           your talent.
•         If you are genetically prone to easily fall prey to depression, it may cause conflicts in relationships.
•         Some scientists theorize that genes also confer susceptibility to stress.

If we can identify our genes and characterize their interactions with the environment, we can have intervention strategies to target them. Therefore, when studying the genetic make-up of individuals to determine their natural predisposition towards certain traits and diseases, it is very important to take into consideration the environmental factors like diet, lifestyle, work environment etc, to be able to characterize their inclination towards these traits and their risk for developing specific diseases.