‘Neoteny, also called juvenilization, is the retention, by adults in a species, of traits previously seen only in juveniles (a kind of pedomorphosis), and is a subject studied in the field of developmental biology. In neoteny, the physiological development of an animal or organism is slowed or delayed (alternatively, seen as a dilation of biological time). Ultimately this process results in the retention, in the adults of a specis, of juvenile physical characteristics well into maturity…
…Neoteny plays a role in evolution as a means by which, over generations, a species can undergo a significant physical change. In such cases, a species’ neotenous form becomes its “normal†mature form, no longer dependent upon environmental triggers to inhibit maturity. The mechanism for this could be a mutation in or interactions between genes involved in maturation, changing their function to impede this process…
…Neoteny is not the only contributing factor affecting maturation in species that may have undergone neotenous changes over the course of their evolution, and its actual involvement in the following examples is not well understood:
- flightless birds—physical proportions resemble those of the chicks of flighted birds;
- humans—with traits such as sparse body hair and enlarged heads reminiscent of baby primates. Lactose intolerance in adults is a form of neoteny now considered normal in certain populations that traditionally consume cow’s milk while most other humans are lactose intolerant as adults. It corresponds to a mutation that permits the digestion of lactose beyond the lactation period.
- pets, such as dogs—which share many physical features with the immature wolf (these same traits were found during the development of the tame silver fox). Such puppy-like traits may have made early dogs seem “cute” and less threatening than wolves, leading to both natural and artificial selection of such dog’
