In this interview with Carolina Biological Supply Company, Dr. Collins discusses the Human Genome Project and how it will impact human health. DNA is the blueprint of the human organism, of all living organisms. It contains the instruction set. But you have to have a certain stretch of that, a packet of that, to actually create an instruction to do a particular thing, and that instruction is called a gene. So a gene is a stretch of DNA that codes for a particular protein.
Genes can be variable in size.
There are about a hundred thousand of them all together in the human genome. DNA is also packaged into chromosomes. There are 46 chromosomes inside each human cell. Each chromosome, therefore, has thousands of genes. It just happens that for purposes of copying the DNA and keeping it all straight, it helps to have them separated into chromosomes instead of just one big piece.