According to the latest edition of Nature Genetics, a team of Japanese researchers has discovered in ear wax the smallest form of genetic difference, known as a single nucleotide polymorphism.
They have shown that just one tiny change in DNA can lead to a change in how the body works and how we look.
The Japanese team found that in northern Asia - Japan and China - the genetic alteration that produces hard, white ear wax (as opposed to sticky and yellow) is more common. It's also more common among Native Americans, suggesting they may have originally come from China.
As you go south and west of China into Europe, Africa and the Pacific, the hard ear wax variation becomes rare. It's least common in the Solomon Islands and France, according to the study.
The mutation that led to people having this kind of ear wax must have happened in northern China. As with most mutations that become common in a particular population, it must have given the people with hard wax some advantage.
The researchers think the advantage is linked to the other characteristic they noted in the hard ear wax brigade. Their sweat apparently doesn't smell as much as the sweat produced by people with the sticky variety.
The researchers believe this may have made them more attractive in the cold climates, where the hard wax populations are found. Where people spent long winters confined in small areas and needed to be close to one another to stay warm, those people who were less smelly may have been more attractive to potential mates.