The definition of epigenetics is the modification of a species over time due to its surrounding environment. The stickleback fish have removed their pelvic and dorsal spines over a duration of time because in their new environment proved unbeneficial. This change is al a demonstration of gene regulation. While the spines severed a purpose in a marine life at one point in time, the freshwater habitat requires a different body structure and composition for the survival. A change in size allowed the stickleback to escape from prey and removing the spines increased the fitness of the fish. The was gene regulation could remove the spines was due to an upstream genetic switch that regulates developmental control genes. Which here called for the deletion
