Prior to the discovery of DNA, it was understood that the obvious differences in one's self - such as facial features and bodily structure - were passed down from generation to generation. However, it is the recent revolution in genomics that has helped us understand how our genetic makeup influences our specific risks of developing complex diseases and disorders, such as heart disease, osteoporosis or cancer. These diseases often manifest following the introduction of many environmental factors to the body - just think of the long list of things your physician says you should do to avoid a heart attack!

What we now understand better is that many different genes are associated with disease or our inability to meet certain health goals, and they interact not only with each other but environmental exposures as well. Sometimes a change in a gene only increases our disease risk if changes to other genes are also present, while in contrast a change in one gene increases our risk of a disease merely when a particular environmental factor is also present. For example, certain variations to the genes called Interleukin-1 that control inflammation in our bodies can increase our risk of heart disease, but likely only if we indulge in certain lifestyle factors such as smoking or an unhealthy diet.

Some differences in our genome exhibit more distinct, well-defined effects because they stop or decrease productivity of a vital protein. For example, the life-threatening blood disorder sickle cell anemia is caused by an inherited trait in the gene that codes for hemoglobin that causes the red blood cell to deform structurally.  Because we have two copies of this hemoglobin code, people with only one gene affected usually go on to live normal lives. Of course not all such changes are medically significant - the presence of ear lobes and a cleft chin are all determined by single genes but do not impact our health and wellness.