What is a gene?

A gene is defined as a section of DNA that controls a trait. This means that genes are responsible for the instructions needed to develop specific traits in an organism, such as eye color, hair type, or the ability to metabolize certain substances. Each gene is made up of sequences of nucleotides, which encode the information necessary to produce proteins or RNA molecules, ultimately influencing the organism's phenotype—the observable characteristics resulting from the interplay between genetics and the environment.

The role of a gene as a functional unit in heredity becomes vital in understanding how traits are transmitted from parents to offspring. This relationship underscores the importance of genes in the principles of heredity, as they are the segments of DNA that carry the information necessary for the hereditary transmission of traits. Understanding this concept forms the foundation of genetics and molecular biology.