As any man who has ever grown a beard has probably noticed before, no matter what color hair sits atop your head, there's a very good chance that you've got lots of red whiskers in the fuzz on your face.
To figure out this exact mystery, the good people over at Motherboard tracked down experts at the Dutch national information centre for genetics and hereditary traits. Here's what a specialist at the center, Petra Haak-Bloem, said.
“Generally speaking, people inherit hair color not only from their parents, but also from their grandparents and earlier ancestors. So it’s entirely possible that one distant ancestor had a hair color that suddenly appears again though a certain combination of genes—and that can be quite unexpected for parents."
The shade of hair color is determined by the amount of melanin, or pigment, in the hair. Your DNA not only encodes what kind of pigment you have, but also how much of it. “For white people the shades are dependent on two sorts of melanin: eumelanine (black pigment) and pheomelanine (red pigment). Hair cells of dark haired people only contain eumelanine. Blondes have less eumelanine. And redheads’ hair contains mostly pheomelanine,” Haak-Bloem says.
In essence, when a person ends up with two mutated genes from both parents—don't worry, it's not a bad thing—Haak-Bloem says that "less pheomelanine is converted into eumelanine. The feomelanine accumulates in the pigment cells and the person ends up with red hair and fair skin.”
That's a lot of scientific jargon, but that's exactly why you're walking around with a half-ginger, half-brown haired beard. Science, man, it always seems to trick us.