What was the first gene discovered by biologists?

The first gene discovered by biologists is often considered to be the "Lac operon" in Escherichia coli, identified in the 1960s by François Jacob and Jacques Monod. Their work elucidated how genes control the metabolism of lactose, laying foundational principles for genetics and molecular Biology. This discovery helped establish the concept of gene regulation and function, significantly advancing our understanding of genetic expression.