Definition: Phaenogenetic refers to a type of genetic material that originated from a single cell, which is believed to have been produced by cells in the womb or during fertilization. This type of genetic material is called a phaeocytosinoid, and it has been found in many species of plants, algae, and fungi. Phaeocytosins are also known as phaeo- or phaeonuclei, which refers to their appearance similar to the nucleus of