The headline for Guy Gugliotta's May 24 news story ["The Neanderthal: A Modern Man With Disease?"] misrepresents my findings published in the Geographical Review. Yes, Neanderthals appear to be iodine-deficient relative to modern humans, but that does not equate to a pathological explanation of Neanderthal. A single genetic mutation affecting thyroid function could account for a multitude of morphologic traits and provide a far simpler solution than the conventional assumption of numerous mutations affecting numerous individual body features.
Anatomically modern humans possess exceedingly efficient thyroid glands acquired through hundreds of thousands of years of evolution, most likely occurring in iodine-rich coastal environments. That efficiency is an established medical fact, regardless of how one interprets its relation to evolution. Daily doses of iodine remain essential for healthy maintenance of many gracile features that distinguish us from earlier hominids. Neanderthals may have missed that thyroid boost, perhaps because they lived inland, where iodine was scarce. A slightly less efficient thyroid would have made them more susceptible to iodine deficiency disorders wherever iodine was scarce, or a substantially less efficient thyroid would have caused them to retain earlier hominid traits even where iodine was abundant.
I favor this "Occam's razor" genetic solution, but one cannot ignore the fact that modern humans living in or near Neanderthal sites would suffer pathologically from cretinism -- the most severe form of iodine deficiency -- if not for daily sprinkles of iodized salt. Naturally, "insiders" will be sensitive, even embarrassed, when "outsiders" ask questions that should have been asked a century ago, but that will be an acceptable price for scientific advancement.
-- Jerome E. Dobson
The writer is a geographer at Oak Ridge National Laboratory.