Several years ago ago, scientists discovered that a gene called ABCC11 determined whether people produced wet or dry earwax. Interestingly, people who produce the “dry” version of earwax also lack a chemical in their armpits that bacteria feed on to cause underarm odor.
“This key gene is basically the single determinant of whether you do produce underarm odor or not,” Day said.
While only 2 percent of Europeans lack the genes for smelly armpits, most East Asians and almost all Koreans lack this gene, Day told LiveScience.
No one knows exactly why gene prevalence varies so much between populations, but its absence in East Asia suggests that being stinky was evolutionarily selected against there over the last several thousand years, he said.