Question: I know that hair colour is to do with genes and stuff, nut how do they really work? How do genes create your kind of, 'image'?

Richard Unwin answered on 17 Nov 2015:

Hi Izzy,

Great question. Although we talk about a gene that makes your hair brown ,or your eyes blue, or your legs long, or whatever, in reality there are many different ‘version’ of each gene in the population. The scientific name for these is ‘polymorphisms’. Each version varies and my give a stronger or weaker signal, so, if your hair is very dark, you have a version of that gene which is strongly ‘on’ and makes lots of ‘colour’. A good way to think about it is like a tap – all taps do the same thing (make water come out), but how much and how fast will depend on the type of tap you have, and how wide the pipe is that it’s connected to.
Since we all have genes that code for the same things, but we all have a mixture of different versions of these, we all look generally the same (two arm, two legs and a head, in roughly the same proportions), but equally we all look slightly different.