Chimera (Genetics)

A genetic chimerism or chimera is a single organism composed of cells with more than one distinct genotype. In animals, this means an individual derived from two or more zygotes, which can include possessing blood cells of different blood types, subtle variations in form and, if the zygotes were of differing sexes, then even the possession of both female and male sex organs. Animal chimeras are produced by the merger of multiple fertilized eggs. In plant chimeras, however, the distinct types of tissue may originate from the same zygote, and the difference is often due to mutation during ordinary cell division. Normally, genetic chimerism is not visible on casual inspection; however, it has been detected in the course of proving parentage.