title: From aardvarks to apples and orchids to ostriches: the simple evolutionary roots of a world of biological complexity and biodiversity.
abstract: Most genes arise by gene duplication, a process that has allowed the evolutionary development of new proteins and peptides with diverse functions, based on modifications of pre-existing sequences. Gene duplication creates both new DNA substrate for the encoding of information, and an information substrate for further modification of already evolved information. Because DNA "wants" to copy itself, both vertically from generation to generation and horizontally due to gene duplication, it creates a great deal of nonsense within the genome called "junk" or "selfish" DNA, which has no present function. However, it acts as an inadvertent evolutionary library and as an autocatalytic substrate for the creation of more DNA containing already-preselected sequences. The process, over evolutionary time, has created large families of related hormones, regulatory peptides, and their receptor and signaling systems, for many of which the functions have yet to be described.
authors.affiliation: Institute of Human Nutrition, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA. jwadelson@hotmail.com
authors.forename: J W
authors.initials: JW
authors.lastname: Adelson
mesh_terms: D000818:Animals; D005075:Biological Evolution; D017753:Ecosystem; D020440:Gene Duplication; D006728:Hormones / Q000235:genetics / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D010455:Peptides / Q000235:genetics / Q000502:physiology
chemical_list: D006728:Hormones; D010455:Peptides