@heyimadeit
I’ve got two red headed sons and one has brown eyes and the other blue.
My DH is strawberry blonde and I’m auburn.
Can anyone tell me how the genes work for red hair!?
Red hair is a recessive gene.
A black haired person can carry one copy of the gene, but won't have red hair, as black dominates.
A brown haired person can also carry one copy of the gene, but also won't have red hair as the brown dominates.
If these two theoretical people meet, settle down and have children, the resulting possible hair colours could be
Black-red
Black-brown
Brown-red
and
red-red
Two 'normal' people, each carrying a red gene have a
50% chance of producing a normal child with red as a recessive gene
25% chance of producing a normal child with no recessive gene
and a 25% chance of producing a red haired child
So the chances of having a red (or blonde) child are pretty slim.
If someone carrying a single copy of the red gene pairs up with a red haired partner, the possibilities are
Black-red
Black-red
red-red
red-red
So they have a
50% chance of producing a normal haired child with a single copy of the red gene and a
50% chance of producing a red haired child.
How the red hair is 'expressed' is another matter entirely.
Eye colour is a complex inheritance
www.nature.com/articles/s41467-018-07691-z
www.cancer.gov/publications/dictionaries/genetics-dictionary/def/snp