Anyone remember the blue/brown eye debate?

[MamaMaiasaura]

I remember their was a big discussion and some research as well to say blue eyed parents could have a brown eyed child.. was looking on bbc website and found this which is cool but says that blue is recessive and if you are with Ewan for example who has bb gg both recessive there is no way you can have brown eyed baby as B is dominant. here this

No, green can be dominant over blue according to the link and genetics lectures.

hmb it was tamum i spoke to before about this and she found a link saying different.. altho bbc is generally a pretty reliable source and my text books say the same. It isnt as black and white as looking at someone and saying what they are going to children as only 23 chromosones from each parent go to child.. no telling which 23. Talking about genetics has anyone read my sisters keeper? just started it myself.

Awen, I know it says this in textbooks, but it really isn't true. There are about a zillion papers in Pubmed saying that it isn't true too. It is broadly speaking the case but it just isn't a single gene, there are many modifiers (about 4 or 5 if I remember). The BBC is like other educators, it uses idealised examples to make things understandable to lay people.

My dp has 3 kids...one has brown eyes, one has blue and one has green. Mums have blue eyes...weird.

tamum - isnt it true however that if as a baby the genes you are given to determine your eye colour contain B you will have brown eyes as this is dominant. Obviously genetics are extremely complex but this basic area is pretty clear. I was pretty sure if you carried the dominant gene that it showed in your genotype.

It is usually the case but not always; it depends on what alleles you carry at the other modifying loci.

bugger - i think i must be thick.. or failed exam - understand alleles but modifying loci got me stumped.

No, not thick- modifying loci are just other genes that influence the expression of the main one (in this case, anyway). They will usually be on other chromosomes, and recombine freely so children will have a different set of alleles at several loci when compared with the parents.

And with the 23 pairs, with 23 from each parents you always (except in rare genetic conditions) get two copes of Chromosome 1, 2 of 2 etc. It isn't a total lottery which chromosomes you get. It is just random assortment of which of the two chomosomes you get.

It is also further confused in that the Phenotype (ie what you look like) is the product of your genotype (geners) and the enviromnet). for example identical don't have identical fingerprints, even though they have identical genes, since their in utero invironment isn't identical.

Awen - have read My Sisters Keeper - I thought it was brilliant!

cool gobble - only just started it but the ethical issues it raises seem very real nowadays. yay hmb i followed that. Oh thanks tamum ofr explaining.. i thought i was being really dumb

can I join this conversation? We have had this discussion many times but no-one has managed to explain to me how..... I have brown eyes, my dh has green, our eldest 2 have blue eyes and the youngest 2 green. presumed the green came from dh, but the blue?

You can carry a gene for blue eyes which is 'masked' by other genes that you have. It is 'silent' if you like. Known as recessive. You are a carrier for blue eyes but don't have them yourself. If your partner also has one of these and your child gets both, blue eyes. But as we posted it is a bit more complicated than that.

However, it is very very rare that two blue eyed parents will produce a dark brown eyed child.

I have dark brown eyes. My husband has blue eyes. Our daughter's are green as two peas.

However, it is very very rare that two blue eyed parents will produce a dark brown eyed child.

ooo - must tell that friend of mine! She'll be dead chuffed that her child is 'very very rare'

Well, my kids are a real mixed bag!

My eyes are brown, their father's eyes were brown and one of them has the brightest blue eyes, one has green eyes and one has brown eyes!

Are they strange or does this just prove that the genes get all mixed up and throw out all sorts of combinations?!

As far as the genes part goes, we each inherit two copies of every gene - one from our mother and one from our father. In the case of the genes for eye colour, it is the particular combination of these two genes that determines which colour is formed. The gene for brown eyes is what is known as 'dominant' - this means that you only need one of the two eye colour genes to be brown for the eyes to be brown. Green may be dominant too, although there are different degrees of dominant, even for brown eyes.

The gene for blue eyes tends to be what is known as 'recessive' - i.e. it is weaker or overshadowed by the brown eye gene. In general a child will only have blue eyes if both of its eye colour genes are blue (however in reality there may be exceptions.)
my dd1 has blue eyes yet her father and i both have brown eyes!!

well my brother has brown eyes yet both my parents and all their other three children have blue...

I give up trying to understand this... especially as my eyes are a really freaked out colour - rings of blue then green with yellow in the middle! DH has brown eyes...DS 1 has very dark blue....[befuddled face]

Why did I call him DS 1... when he's our only one and the one on the way is a girl? Hmmmm.

looks brainless, has a bimbo moment

DH has a friend with violet eyes....would he have violet eyed children? And what about people with no eye colour what then?

my dp is brown eyed and I am blue eyed.

my first two children brown eyed and dark brown hair ...second two blonde and blue eyed!

Well both my parents have blue eyes but mine are hazel, so two blue eyed parents don't necessarily have a blue eyed child.
And hazel eyed me and brown eyed dh have had two bright blue eyed children.
Curiouser and curiouser.

haven't read thru thread, but

my brother has blue-grey eyes, but one half of one iris is brown!

what about david bowie - one brown eye, one blue, i believe...?

fastasleep, stop teasing!