Intraspecies Chimeras Produced in Laboratory Settings (1960-1975)

When cells?but not DNA?from two or more genetically distinct individuals combine to form a new individual, the result is called a chimera. Though chimeras [2] occasionally occur in nature, scientists have produced chimeras [2] in a laboratory setting since the 1960s. During the creation of a chimera, the DNA molecules do not exchange genetic material (recombine), unlike in sexual reproduction or in hybrid organisms, which result from genetic material exchanged between two different species. A chimera instead contains discrete cell populations with two unique sets of parental genes [3]. Chimeras can occur when two independent organisms fuse at a cellular level to form one organism, or when a population of cells is transferred from one organism to another. Chimeras created in laboratories have helped scientists to identify developmental mechanisms and processes across species. Some experiments involving chimeras [2] aim to provide further knowledge of immune reactions against disease or to create animal models to understand human disease.