How living things get to be what they are is a question that has occupied philosophers and scientists for a very long time. In the past two or three hundred years, the focus has been on what Gregor Mendel has called units of heredity or the physical elements that are transmitted from parents to offspring. These are now called genes, and have become an integral part of the conversation about human beings and their health.
What genes are
The cells of living beings contain chromosomes, which are recognized as the bearers of inheritable information. Chromosomes contain a double helix of DNA (deoxyribonucleic acid) and protein. DNA is a long series of units called nucleotides. It is believed that DNA makes RNA (ribonucleic acid), which differs from DNA in chemical composition. RNA translates the information coded in the DNA and prompts the specific development of various proteins in the body.