Xenotransplantation, or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenografts or xenotransplants. It is contrasted with allotransplantation, syngeneic transplantation or isotransplantation and autotransplantation. Xenotransplantation is an artificial method of creating an animal-human chimera, that is, a human with a subset of animal cells. In contrast, an individual where each cell contains genetic material from a human and an animal is called a human–animal hybrid.