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Original poster

to really not understand the genetics involved in eye color?

213 replies

CheerfulYank · 11/10/2011 06:40

It's all very confusing. Blush I remember something about punnett squares, and two blue eyed people not "being able" to have a brown-eyed child, but now I think that's a myth, isn't it? Or something?

My eyes are a very pale blue, DH's are brownish hazel. DS's are blue. I was just on a website "predicting" your future children's eye colors and it said they would be brown as DH's are brown, but that's obviously not the case.

Can someone who did not spend high school biology class flirting with their lab partner explain this to me? Blush In small words?

OP posts:
Kayzr · 11/10/2011 07:29

Pascha, eyes usually change colour by 6 months old if they're going to change.

Kayzr · 11/10/2011 07:30

Is hair similar? I have brown hair, XH has red hair and DS2 is blonde

troisgarcons · 11/10/2011 07:33

If you have one brown, one blue, you'll have brown eyes

no - you could have either, if the brown eyed person has a recessive blue gene.

HooberGoober · 11/10/2011 07:33

YAdefNBU not to understand it because I don't think anyone does fully - it is still an area of active research! However, the thing everyone gets taught at school is a massive oversimplification I'm afraid.

In genetics you can have what are called monogenic traits - controlled by a single gene - and polygenic traits - controlled by several genes. Truly monogenic traits are actually quite rare in the scheme of things as humans are complicated beasties! The simple blue/brown recessive/dominant model assumes eye colour is monogenic, but it turns out it isn't. At least 6 genes have been implicated so far but there may well be more. Even assuming that there are only 2 possible variants (called 'alleles') in each gene gives a lot of potential combinations, and it is highly likely that there are more than 2 alleles for each gene. Hence the enormous variety in eye colour and pattern that you see in people, and the fact that any two parents can produce a child with pretty much any eye colour!

Bubbaluv · 11/10/2011 07:35

I think both parents have to pass on a red hair gene to have a red head child. Were you born dark or did you start blonde and get darker?

HooberGoober · 11/10/2011 07:36

Yes, hair is similar, and in fact may involve some of the same genes as eye colour, and also skin tone, which is one reason why some hair/eye/skin combinations are more common.

Alouiseg · 11/10/2011 07:37

And all before breakfast?

Bubbaluv · 11/10/2011 07:42

Xed posts with hoobergoober, who pointed out again that it's not that simple.

andthisisme · 11/10/2011 07:43

I'm really glad you posted this as I was only yesterday wondering about it.

I have blue eyes. DP has brown eyes. I, like most people, assumed that our children would have brown eyes.

They both have a very strange (but beautiful) green/hazel mix. I actually won't know what to put if I ever have to fill out "eye colour" on a form.

I have since discovered that DPs Dad, like mine, had green eyes!

OddBoots · 11/10/2011 07:47

I have had some of my genetics tested (just for my own interest) and by current research my SNPs (genes thought to be involved in this area) say I should have blue eyes but my eyes are yellowy green. It is a far from simple business.

whackamole · 11/10/2011 07:48

The way I remember it is like this:

BB means brown eyes
bb means blue eyes
Bb means brown eyes (as the capital - ie brown - is dominant)

I have brown eyes, OH has blue. Therefore, we can surmise that I must have Bb (my mum has blue eyes so this makes sense) and OH must have bb, so there are more b's to counteract the B's.

Does this make sense??!

BatmanLovesRobin · 11/10/2011 07:48

I bet my friend's mum wish she knew this, before she had her brown eyed child and had to admit to an affair she'd had Confused

PaschaTheSlasher · 11/10/2011 07:51

I thought it was generally set by 6 months but gradual changes could take up to 3 years? And puberty can do it too.

His eyes at 13 months are different from 10 months.

Robotindisguise · 11/10/2011 07:53

Troisgarcons, at that point I'm talking about the genes you have, not the eye colour of the parents.

TonksmarriedaWerewolf · 11/10/2011 07:55

I have brown eyes, as does my dad. His parents were blue and brown.
DH has blue eyes going back generations.

DD1 has very dark brown eyes and hair
DD2 has that lovely olive/hazel combo and similar hair - she'll never need highlights! Envy
DS has bright blue eyes and blonde hair

Fascinated by the whole genes thing!

CotherMuckingFunt · 11/10/2011 07:58

Hoober Are you my mum?

Grin
IwoulddoPachacuti · 11/10/2011 08:03

I'm trying to take this in because I'm genuinely interested but I've not long woken up and my mind keeps drifting!

I have dark brown eyes. My dad had Hazel eyes and my mum has green. I married a blue eyed man and have Ds who has blue eyes with a smudge if brown in one, and DD who has green eyes. Hmm Confused

I really am interested but I will come back to this later on once I've had about 3 coffees and try and take it in Grin

IwoulddoPachacuti · 11/10/2011 08:04

So tired I have repeated myself within 3 paragraphs Blush [thick as shit on a bottle]

Kayzr · 11/10/2011 08:10

Bubbaluv nope I've always had really dark hair. Everyone in my family is dark haired. XH's sisters are dark blonde/light brown. So I'm guessing there's some recessive thing going on.

SardineQueen · 11/10/2011 08:10

I agree with the others who have said that the science taught to children in school is often simplified (and sometimes quite wonky indeed!) and that in real life it is much more complicated than that. And also that the human body is terribly complex and even things that we think we know later turn out to be not the full picture or just plain wrong!

Cheeptrickortreat · 11/10/2011 08:13

My Dad has black hair and brown eyes my mum had blond hair which turned brown in her 20ys and blue eyes.

DSis1 has blond hair and blue eyes
Dsis2 has brown hair and blue eyes
Exbro has brown hair and blue eyes
Me red hair and blue eyes

Went i'm with my sisters noone ever believes we are sisters Shock

GingerWrath · 11/10/2011 08:39

I have Brown eyes, DH has Hazel, DD has brown round her pupils and slate grey outside, dunno what happened there!

notcitrus · 11/10/2011 08:56

There's at least a dozen genes involved in eye colour, encoding various amounts of the brownish and bluish and variant greyish and greenish pigments and how they get arranged in the iris. So while generally brown eyes, especially very dark consistent brown ones, will dominate over blue ones (especially very blue ones with no traces of brownness), it's one heck of a lot more complicated than that.

Result: despite expecting ds to have brown hair and eyes (DH has both, nearly black hair, I have brown hair that used to be near black, but blue-green eyes), ds is blondish and has stunning eyes with flecks of blue, green and grey - he's the image of my mum facially, only with DH's mum's physique and facial expressions.

Blood groups are also a bit more complicated than taught in school - though not quite as commonly complicated as clinics make out when trying to gloss over the fact that your chap isn't the father of your baby...

mousyfledermaus · 11/10/2011 09:09

my parents have blue eyes, all my siblings and I have blue eyes but on my fathers side are a few red-heads with striking green eyes.
my pil have blue eyes, their dd has blue eyes, my dh has hazel eyes.
my ds has very striking blue eyes, the dd is strawberry blonde with a peculiar eye colour between green and blue (depending on what she is wearing).

celebmum · 11/10/2011 09:10

Both my parents have dark hair & brown eyes, my older sister and younger brother both have red hair & Hazel eyes.. I (born between said brother and sister!) have brown hair and Hazel eyes!? Confused

What hapened to my Ginger?!?

I married a blue eyed blonde and my DS is blue eyed and blonde too..