Biston betularia: light phenotype (left), dark phenotype (right)WIKIMEDIA, OLAF LEILLINGER (LEFT, RIGHT)Scientists have finally identified the genetic change that enabled the black peppered moth (Biston betularia) to change shades—from a light, speckled color to a dark brown hue—to camouflage itself against Britain’s soot-blackened trees during the Industrial Revolution: a mutation in a gene called cortex, according to a study published last week (June 1) in Nature. The same gene was found to control color in butterflies, according to another study published at the same time in the same journal.
In the former study, Ilik Saccheri of the University of Liverpool, U.K., and colleagues crossed light- and dark-color moths and mapped their genetic differences. From a genetic sequence of 400,000 bases, the researchers homed in on 87 differences, which they tested individually. The team finally traced the color change to a transposon or “jumping gene” located in the cortex gene.
“It’s this huge chunk of DNA that doesn’t itself code for anything, but somehow disrupts the nature of the gene,” Saccheri told The New York Times.
By examining the genetic variance around this mutation, Saccheri’s team estimated that the hue-altering mutation occurred within a 10-year period around 1819, which fits with records of the black moths’ first sighting in 1848, according to BBC News.
“This ...
