In the simplest terms, the adjective “genetic” means anything that pertains to a person’s gene sequence that exists within every living cell. Genes are the basic component of heredity in humans and other living organisms.
Genes are made up of DNA, or deoxyribonucleic acid. According to the Human Genome Project – a multinational research endeavor designed to identify and map the genetic sequence of humans – we have an estimated 20,000 - 25,000 genes.
Remarkably, approximately 99% of genes are the same in all people, with the remaining tiny proportion responsible for the differences we see in height, skin color, weight, and other physical traits.
The genetic theory of aging suggests that longevity is also determined by our genes, and some research – such as studies involving identical twins – supports this hypothesis. Other studies have estimated that a person’s lifespan is only about 25% attributable to their heredity, and much more likely to be influenced by lifestyle factors like diet and exercise, and harmful habits like smoking or alcohol abuse.
What is a gene? US National Institutes of Health “Genetics Home Reference” Public Information Sheet. Accessed Aug.27, 2012.