Genes and environment work together to shape who we are. Because environment includes everything we experience and come into contact with from conception through death, it also plays an awesome and extremely complex role. Even scientists disagree on exactly how to define a gene. Generally, a gene is a sequence of DNA that codes for a single protein.
Proteins do the work of the body, building structures and catalyzing biochemical reactions.
Because what scientists announced Monday is basically a string of 3 billion letters, not even scientists know how many genes there are. In a betting pool set up recently by one scientist, estimates ranged from about 34,000 to 140,000. That means that of the 3 billion letters in the human genetic code, each of us differs in about 300,000. Remarkably, those variations are scattered throughout the species without regard to what we think of as race. Scientists have been amazed at how genetically similar humans are to other species.