One of the funniest things that happened when young men started growing beards was their realisation that there was a little bit of red in there.

After all, many of them had, for years, tuned anyone who had read hair.

So why do men, who don’t have even one strand of red hair on their head, have it in their beards?

According to Huffington Post:

“The genes that determine hair colour are so-called ‘incomplete dominant hereditary traits.’ This means that there isn’t one single gene that’s dominant over the rest, but all genes influence each other,” Petra Haak-Bloem, a specialist at Erfocentrum, the Dutch national information center for genetics, told Motherboard.

The red hair itself is caused by a mutation in what researchers call the MC1R gene.

Having two mutated genes gives someone all red hair, but having just one can give a person red hair in unexpected places. In non-Gattaca terms, that means even if a gene that signals brown hair is dominant in your family, another gene for red hair may still be present in your genetic code.

So if you’ve got a red beard, someone at some point in your family had red hair, but those genes can express themselves differently in different people across different generations.

And there you have it.

[source:huffingtonpost]