A chimera is a creature from mythology that combines parts from different animals. In ancient Greek mythology, the Chimera was depicted as a fire-breathing monster with the body of a lion, a goat's head rising from its back, and a serpent for a tail. This fantastical being symbolizes the blending of various traits into one entity. In modern science, the term "chimera" also refers to an organism that contains cells from two or more different genetic sources. For example, a genetic chimera can occur naturally, such as in some twins, or be created in laboratories for research purposes. These chimeras help scientists study genetics and disease.