was ist ein gen — what does this mean exactly?

A gene is the fundamental physical and functional unit of heredity. It consists of a segment of DNA that contains the instructions for making a functional product – typically a protein, sometimes an RNA molecule. The modern definition is more nuanced: genes also include regulatory sequences that control when and where the product is made. Humans have an estimated 20,000–25,000 protein-coding genes, but the majority of DNA is non-coding, with regulatory or structural roles. In direct-to-consumer genetic tests (e.g., MyBody-X), specific gene variants (SNPs) are analyzed for associations with traits like metabolism or inflammation. However, a single gene rarely determines a complex trait; environment, lifestyle, and many genes interact. The concept of a gene is well-established (evidence: human-strong), but its practical use in personalized health advice is often overstated. Consumers should understand that a gene is a blueprint, not a destiny.