Editing Epicanthic fold (section)

== Possible evolutionary function ==
The epicanthic fold is often associated with greater levels of fat deposition around the eyeball. The adipose tissue is thought to provide greater insulation for the eye and sinuses from the effects of cold, especially from freezing winds, and to represent an adaptation to cold climates. It has also been postulated that the fold itself may provide a level of protection from [[snow blindness]]. Though its appearance in peoples of Southeast Asia can be linked to possible descent from cold-adapted ancestors, this does not explain its occurrence in various African peoples. The epicanthic fold found in many African people has been tentatively linked to protection for the eye from the high levels of [[ultraviolet]] light found in desert and semi-desert areas.<ref>{{cite book|editor-last=Lang |editor-first=Berel |year=2000 |title=Race and Racism in Theory and Practice |url=https://books.google.com/books?id=VOtU0FzgFPUC&pg=PA10|publisher=Rowman & Littlefield|pages=10–11 |isbn=9780847696932}}</ref>

The exact evolutionary function and origin of epicanthic folds remains unknown. Scientific explanations include either random variation and selection (presumably [[sexual selection]]), or possible adaption to desert environment and/or high levels of ultraviolet light found in high-altitude environments, such as the [[Himalayas]].

Dr. Frank Poirier, a physical anthropologist at [[Ohio State University]], said that the epicanthic fold among Asian people is often explained as part of an adaptation to severe cold or tropical environments, however he suggests that neither of these explanations are sufficient to explain its presence in East and Southeast Asia, and notes that the fold can also  be observed in [[Irish people|Irish]] and African people. He attributes the epicanthic fold to [[pleiotropic]] genes that control more than one characteristic or function. He also did not offer an explanation for the origin of epicanthic folds.<ref>{{cite news |title=ORIGIN OF SHAPE OF ASIAN EYES IS STILL A MYSTERY TO SCIENTISTS |url=https://www.chicagotribune.com/news/ct-xpm-1985-10-13-8503100141-story.html |work=Chicago Tribune}} "Dr. Frank Poirier, a physical anthropologist at Ohio State University, says the classical explanation of epicanthic fold depicts it as an adaptation to the tropical and arctic regions where many Asians live. The fold is described as a sun visor protecting the eyes from overexposure to ultraviolet radiation or as a blanket insulating them from the cold. According to Poirier, the problem with this theory is that a substantial portion of the Asian population evolved in areas outside of the tropical and arctic regions. In addition, he says epicanthic fold is not limited to Asians. ''John F. Kennedy had a variance of the fold and it is found among Europeans, especially the Irish,'' he said. ''It's just less prevalent.'' The fold is also found among infants worldwide. Poirier attributes the fold to pleiotropic genes--single genes that control more than one characteristic or function--but he has no explanation for its origin."</ref>