Chimera (genetics)
A chimera or chimaera is a single organism (usually an animal) that is composed of two or more different populations of genetically distinct cells that originated from different zygotes involved in sexual reproduction. If the different cells have emerged from the same zygote, the organism is called a mosaic. Chimeras are formed from at least four parent cells (two fertilized eggs or early embryos fused together). Each population of cells keeps its own character and the resulting organism is a mixture of tissues. Chimeras are typically seen in animals; there are some reports of human chimerism. Plant chimeras are discussed separately.
This condition is either inherited, or it is acquired through the infusion of allogeneic hematopoietic cells during transplantation or transfusion. In nonidentical twins, chimerism occurs by means of blood-vessel anastomoses. The likelihood of offspring being a chimera is increased if it is created via in vitro fertilization. Chimeras can often breed, but the fertility and type of offspring depends on which cell line gave rise to the ovaries or testes; varying degrees of intersexuality may result if one set of cells is genetically female and another genetically male.
Read more about Chimera (genetics): Tetragametic Chimerism, Microchimerism, "Parasitic" Chimerism in Anglerfish, Germline Chimerism, Human Chimeras, Chimeras in Research, Mouse Chimeras, Legislation
Famous quotes containing the word chimera:
“I was able to believe for years that going to Madame Swann’s was a vague chimera that I would never attain; after having passed a quarter of an hour there, it was the time at which I did not know her which became to me a chimera and vague, as a possible destroyed by another possible.”
—Marcel Proust (1871–1922)