What best describes how gene expression affects traits?

Gene expression is the process through which information from a gene is used to produce a functional product, typically a protein. This process plays a crucial role in determining the traits of an organism because proteins are essential for the structure and function of cells, tissues, and organs.

When a gene is expressed, it undergoes transcription to form messenger RNA (mRNA), which is then translated into a specific protein. This protein can function in structural roles, serve as enzymes that catalyze biochemical reactions, facilitate cellular signaling, or participate in various other biological processes. The particular set of proteins synthesized in a cell ultimately gives rise to the observable traits, or phenotypes, of that organism.

For instance, variations in gene expression can lead to differences in pigmentation, size, shape, and other physical characteristics. Therefore, the influence of gene expression on the synthesis of proteins that define traits is a foundational concept in genetics and biology, highlighting the direct link between genes and observable traits.