The term "expressed" in a biological context typically refers to the process by which genes are activated to produce their corresponding proteins or functional products. When a gene is "expressed," it means that the information encoded in that gene is being used to synthesize RNA and, subsequently, proteins, which contribute to the organism's phenotype—the observable traits or characteristics.
To read or denote a gene, scientists often use specific nomenclature or shorthand notation that can include gene symbols (like "BRCA1" for a breast cancer susceptibility gene) or standardized formats that represent the gene's location or function.
In summary, when we say a gene is "expressed," we imply that it contributes to the phenotype, which is what can be physically seen in the organism. This expression can be influenced by various factors, including environmental conditions, developmental stages, and regulatory mechanisms.