A number of different patterns led Darwin to the inescapable conclusion that the biological world was shaped by evolution. Among these patterns is the tendency for similar forms, forms now recognized as similar due to genetic relationships, to clump together geographically. Thus hummingbirds, pocket gophers, and packrats are strictly New World, while Norway rats and House Mice were strictly Old World until historic introduction into our western continents.
Exceptions to such clustering imply emigration from the homeland. When
we look at the distribution of our nearest living nonhuman and early fossil human
relatives, we find them clustered in Africa. The indications are that mankind spread
out from that continent, beginning perhaps some 60,000 years ago. Now the Genographic
Project is aiming to analyze the DNA of some 100,000 indigenous people to reconstruct
the migratory pathways. As populations moved away from their original homeland, genetic
changes occurred through time, laying down a genetic trail that the research should
reveal. Soon, we may be able to trace the routes taken by the indigenous peoples of our
Chihuahuan Desert, immigrants all.
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.
Sever, M. 2005. Tracing human migration. Geotimes 50:24-26.