Recent studies show peoples of northern European descent often have a hereditary factor that causes their cells to produce more heat than in people who lack this genetic twist. This appears to be an adaptation to the glacial cold of the last ice age. It has, of course, a cost. Production of extra heat requires extra food. We can speculate that the people of northern Asia likewise had this or a similar adaptation, which brings up a fascinating question. What happened when the ancestors of today's Native Americans left Eurasia and moved south into the temperate and tropical regions of the New World?
The Chihuahuan Desert certainly would have been a test for people
settling down in it. The generally warm temperatures, especially when compared to those
of the ice ages, would no longer require the extra metabolic heat. Ominously, during
famine, the extra calories required by bearers of the trait could mean starvation while
those with different genes survived. We can predict that few if any of the modern
descendants bear this once vital genetic quirk.
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.