How are epigenetic inheritance and Lamarck’s original theory different?

It is a common misconception that Lamarckism and epigenetics are identical; while both involve the inheritance of traits acquired during an organism's lifetime, they differ significantly in their biological mechanisms and scientific standing.12

Lamarck’s Original Theory
Proposed by Jean-Baptiste Lamarck in 1809, this theory suggested that physical changes resulting from an organism's activities—such as the increased use or disuse of an organ—could be directly transmitted to offspring. Lamarck believed these acquired characteristics accumulated over time to drive species evolution. This doctrine was largely discredited by the 1930s because it lacked a known mechanism for how bodily (somatic) changes could be encoded into the germ cells responsible for reproduction.1234

Epigenetic Inheritance
In contrast, epigenetics is the study of chemical modifications to DNA or associated proteins (such as histones) that influence gene expression without altering the underlying genetic sequence. Some of these modifications can be passed to offspring. Unlike Lamarck’s theory, which focused on physical bodily modifications, epigenetic inheritance involves specific molecular signaling that regulates how genes are turned on or off, providing a modern, scientifically verified explanation for how certain environmentally influenced traits can be inherited.52