Here is the definition taken from the Human Genome Project, "A genome is the complete collection of an organism's genetic material. The human genome is composed of about 20,000 to 25,000 genes located on the 23 pairs of chromosomes in a human cell.

A single human chromosome may contain more than 250 million DNA base pairs, and scientists estimate that the entire human genome consists of about 3 billion base pairs.

In the past eighteen months, scientists discovered more than 100 genetic variations that affect older people, such as: type 2 diabetes, asthma, Alzheimer's disease, osteoporosis, high blood pressure and heart disease.

Genetic science is moving so fast that people now in their 60's-80's will see medical innovations that will touch their lives.

Francis Collins, MD, a leader in the Project, was astounded to see the huge amount of information derived from the genome, particularly in regards to older people.

As an example he cited age-related Macular degeneration, an eye disease troubling almost 2 million, visually impaired Americans. "Using new genomic tools we've discovered two genes that account for about 60% of the risk- the rest is smoking. But we were surprised. These genes are involved in inflammation, and everybody was thinking macular degeneration was caused by aging in the back of the eye."

Macular degeneration tests are now being made using anti-inflammatory drugs, a complete change in the way it was formerly viewed.

Many scientists believe that the Human Genome Project has the potential to revolutionize both therapeutic and preventive medicine by providing insights into the basic biochemical processes that underlie many human diseases.