The first discovery, published in Molecular Biology and Evolution, identifies a genetic mutation present in humans that is not present in other vertebrates. This mutation, which is present in AHR caused increased transcription of enzymes in the cytochrome P450 enzyme family, which metabolize foreign molecules. The study shows that a Ala 381 Val substitution in human AHR is the cause of the increased activity (1.) The researchers involved postulate that the toxins in smoke may have selected for this mutation.
The discovery of fire, while distinguishing us in an advantageous manner, may have simultaneously led to cultural practices with negative effects. Biologists at the University of Wales have used mathematical modeling to formulate the theory that fire, while bestowing numerous advantages on its discoverers, may have led to the facilitated transmission of infectious diseases. Increased exposure while sitting around the fire led to transmission, and inhalation of the smoke led to lung damage.
1. Troy D. Hubbard, Iain A. Murray, William H. Bisson, Alexis P. Sullivan, Aswathy Sebastian, George H. Perry, Nina G. Jablonski, and Gary H. Perdew
Divergent Ah Receptor Ligand Selectivity during Hominin Evolution
Mol Biol Evol (2016) 33 (10): 2648-2658 first published online August 2, 2016 doi:10.1093/molbev/msw143