Some fish species reproduce through a method of parthenogenesis called gynogenesis, in which a female will produce an already fertilized and viable egg. This method may be observed in Poeciliopsis monocha and Poeciliopsis lucida. Normally there is a breeding population of diploid fish of each of these species. However, there is also a triploid population of female only monocha-lucida-lucida fish (MLL). These fish produce triploid MLL eggs. Oddly enough, even though there is no genetic transfer between egg and sperm, a diploid lucida sperm is still required in order to activate the MLL egg. Once activated, this egg will develop into a female MLL adult. The fish that comes from this egg is always a triploid female, a genetic clone of its mother and all the fish in its lineage before it.