[quote Kanaloa]@Dustyblue
I didn’t know it worked like that! How interesting.
I’m a natural ginger and only my youngest is but I always just presumed the others took after their dads. Does that mean my DH must have a secret redhead gene? Or have I confused it?[/quote]
Yes, as far as I understand it, your DH has a recessive red hair gene.
This is a basic explanation:
"So let’s imagine that there’s one gene that controls hair color. The different alleles of this gene could be “brown hair”, “blonde hair” and “red hair”. If you have the brown allele of the gene, you have brown hair. If you have the blond allele, you have blonde hair. And if you have the red allele, you have red hair.
But it’s not so simple - you don’t only have ONE allele for each gene. You actually have two: one from your mom and one from your dad. They could both be for the same hair color… or they might be for two different colors.
It may seem obvious that if you have two brown hair alleles you will have brown hair. But what if you have “brown DNA” plus “blonde DNA”? Or brown plus red, or blonde plus red?
It turns out that brown hair DNA is stronger than the other colors. You only need one brown allele to have brown hair. It is a dominant trait.
The DNA for blonde or red hair is not as strong as brown. In order to have blonde hair, both of your alleles need to be blonde. The same is true for red hair. These are recessive traits.
The DNA for blonde hair and red hair are about equally strong. People who have DNA for both often have strawberry blonde hair.
Putting it all together you get:
• Brown DNA + brown DNA = brown hair
• Brown DNA + red DNA = brown hair
• Brown DNA + blonde DNA = brown hair
• Blonde DNA + blonde DNA = blonde hair
• Red DNA + red DNA = red hair
• Red DNA + blonde DNA = strawberry blonde hair"
There are online charts that probably explain it better!