What are genes?

Genes are defined as stretches of DNA that contain the instructions for producing specific characteristics or traits in an organism. They serve as the basic units of heredity, passing on information from one generation to the next and ultimately influencing an organism's biological functions and physical attributes. Each gene encodes for particular proteins or functional RNA, which play essential roles in the development and functioning of the organism.

Physical traits displayed by an organism arise from the expression of various genes, but they are not the definition of what a gene is. Additionally, genes are found in both plant and animal cells, so the notion that they are exclusive structures to animal cells is incorrect. While mutations can affect the physical appearance of an organism, they are changes within the genes themselves, not synonyms or definitions for genes. Thus, identifying genes purely as stretches of DNA specific to characteristics provides the most accurate and clear understanding of their function and role in biology.