What are genes primarily composed of?

Genes are primarily composed of large, complex molecules called DNA (deoxyribonucleic acid). DNA carries the genetic information necessary for the growth, development, functioning, and reproduction of all living organisms. Each gene is a specific sequence of nucleotide bases (adenine, thymine, cytosine, and guanine) within the DNA that encodes instructions for the synthesis of proteins. This fundamental role emphasizes the importance of DNA as the blueprint for biological characteristics and heredity.

While proteins are encoded by genes, they are not what genes themselves are composed of; rather, proteins are produced as a result of the instructions that genes provide. Chromosomes, which are structures that organize and contain DNA, include many genes but are not the direct components of genes themselves. RNA sequences play a role in the expression of genes but are not the primary composition of genes; rather, they serve as intermediaries during the process of translating genetic information into proteins. Thus, the characterization of genes as being composed of DNA reflects their essential role in genetics and biology.