gene

Imagine your DNA as a very long instruction book. A gene is one small part of that book, carrying directions that help a living thing grow, work, and develop. These directions can affect traits such as eye color, blood type, or how the body makes certain proteins.

You inherit genes from your parents, which is why family members often share features. Different versions of the same gene can lead to differences, such as one person having brown eyes and another having blue. Genes help shape many parts of life, but they usually work together with other genes and with the environment, not all by themselves.

A gene is the basic unit of heredity: a section of DNA that contains instructions used by cells. If DNA is like a very long book, a gene is like one passage in that book, written in a chemical code. Those instructions often help the body make proteins or control how cells behave.

Genes play a major part in inherited traits, so they can affect features such as eye color, blood type, height, and many aspects of how the body grows and functions. They can also influence the risk of certain diseases. Still, most traits do not come from a single gene alone. Many traits are shaped by several genes working together, and environment matters too.

You receive genes from both parents, which is why relatives often resemble one another. A gene may exist in different versions, called alleles, and those different versions can lead to differences between people. Changes in DNA, sometimes called mutations, can also alter how a gene works.

Genes are central to biology, medicine, and heredity. They help explain how traits are passed on, why living things vary, and how the body follows its built-in instructions from one generation to the next.