Home Page Science Frontiers
ONLINE

No. 82: Jul-Aug 1992

Issue Contents





Other pages


Other Interesting Sites


 


 


 


 


 


 


 


 


 

 

EVEN TODAY NATURAL SELECTION IS MOLDING HUMAN POPULATIONS

Nauru is a remote Pacific atoll with a population of 5,000 Micronesians. Formerly, the Nauruans led energetic lives -- fishing, subsistence farming -- and they were slim and healthy. Then came colonization and phosphate mining; with these came wealth, imported caloriepacked food, sedentary lives, obesity, and, unhappily for this tropical paradise, diabetes. The incidence of diabetes mellitus shot up to 60%, an astounding statistic by world standards. On one of the wealthiest of the Pacific islands, the inhabitants have the shortest life spans! The same scenario is being played out in other parts of the world where life styles have changed drastically; for example, some Polynesians, American Indians, and Australian aborigines are similarly afflicted. Furthermore, an epi-demic of diabetes mellitus is anticipated as the "benefits" of civilization are brought to India and China.

Two questions must be answered: (1) Why is the incidence of diabetes mellitus only 8% among American junkfood-eating couch potatoes? Probable answer: natural selection has already modified the American genotype by eliminating those who are supersensitive to diabetes mellitus under conditions of rich diets and sedentary lives. (2) Why are modern populations still living under Spartan conditions so sensitive to diabetes in the first place? Possible answer: the so-called "thrifty genotype" hypothesis. In this view, the genotype that is sensitive to diabetes also confers survival advantages in societes where food supplies are meager and unpredictable. This genotype provides for a hair-trigger release of insulin for the rapid conversion of rare food gluts into body fat deposits that will sustain the individual during the next famine. Unfortunately, when rich food is continuously available, people with this "hairtrigger" genotype succumb to diabetes.

(Diamond, Jared M.; "Diabetes Running Wild," Nature, 357:362, 1992.)

From Science Frontiers #82, JUL-AUG 1992. 1992-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:

Quotes

  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987