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to really not understand the genetics involved in eye color?

(214 Posts)
CheerfulYank Tue 11-Oct-11 06:40:42

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?

Proudnreallyveryscary Tue 11-Oct-11 06:47:41

I too am the antithesis of a scientist and spent my biology classes reading Just Seventeen within the pages of a dusty old tome, but I think two blues can't make a brown.

My dh and I are very dark with dark eyes and my son has bright blue eyes and I can't tell you how many comments I got about 'I didn't think that was possible', the commentator looking me up and down suspiciously! Those people were even denser than me it seems.

Proudnreallyveryscary Tue 11-Oct-11 06:48:26

Btw three of our parents have blue eyes so I'm guessing that's where ds's baby blues have come from.

CotherMuckingFunt Tue 11-Oct-11 06:49:59

My mum (biologist, studied genetics) told me that what you learn at school is all bollocks because there are mutant genes and its' very complicated. I made a noise that seemed to indicate interest at this. She then went on to explain how it worked.

Once she had finished I had worked out how a particularly tense situation in Neighbours could be resolved and what I was going to feed the kids for dinner but was none the wiser to eyes. Sorry!

CotherMuckingFunt Tue 11-Oct-11 06:51:19

I do remember something about mutant genes and dominance and recessive blah blah blah...

<should pay more attention>

CheerfulYank Tue 11-Oct-11 06:53:53

For a long time I think the consensus was that if you had blue eyes, that meant you only had blue eyed genes, because if you had a brown one it would be dominant and your eyes would be brown. BUT apparently research has come up showing that more genes than previously thought are responsible for eye color, so it is rare but possible for two blue eyed people to have a brown eyed kid?? confused

My dad is blue eyed and so are his brothers, and all three of them married dark haired, dark eyed women, and for the most part all my cousins and I have our family's signature slightly creepy pale eyes. So our mothers probably passed a blue gene to us, despite having brown eyes themselves...

I am making myself sound thicker by the minute, aren't I? blush

troisgarcons Tue 11-Oct-11 06:54:02

in short you ahve dominant and recessive genes.

Brown is dominant, blue is recessive. two brown eyes people can have brown ir bllue eyes children. Two blue eyed can't have brown eyes. A parent of each can have either !

Hope that muddled you more!

I have blue eyes, both my parents had blue eyes.
My DP has brown eyes, his brother has blue eyes, His mother had blue, his father had brown.
All my children have brown eyes.

Somewhere in there is a lurking blue gene - its the luck of the draw if it ever comes out though. Brown will dominate.

troisgarcons Tue 11-Oct-11 06:55:24

*So our mothers probably passed a blue gene to us, despite having brown eyes themselves...

Thats right!

JoandMax Tue 11-Oct-11 06:55:51

What about green eyes??? Where do they fit in?

duckdodgers Tue 11-Oct-11 06:55:52

Blue is a recessive gene and brown is dominant I remember that. There are 2 bits for each eye colour (cant remember what they are called!) so someone with brown eyes either could have the 2 bits for brown or 1 bit for brown and 1 bit for blue - but obviously have brown eyes.

Blue eyes are just 2 bits for blue. If your partner has brown eyes and their genes are 1 bit blue cross that with someone with blue eyes and you have a 1 in 4 chance of having a blue eyes baby. Does that make sense grin

troisgarcons Tue 11-Oct-11 06:57:09

Green eyes - ah! science lessons didnt cover those, nor grey nor hazel!

CotherMuckingFunt Tue 11-Oct-11 06:58:22

Dh has brown eyes and I have blue.

Ds has blue eyes so dh carries the blue eyed gene.

Dd has stripey eyes - a circle of brown surrounded by a circle of blue so dh and most certainly not me because i'm far to fab has a mutant gene raging away in there somewhere.

Kayzr Tue 11-Oct-11 07:03:47

I have green eyes and XH has brown eyes but both the boys have blue eyes. Both our mothers have blue eyes. So maybe it's from them.

CotherMuckingFunt Tue 11-Oct-11 07:05:28

I have just emailed my extremely clever-and-does-something-with-placentas-and-cancery-things scientist SIL because I need to know now.

CheerfulYank Tue 11-Oct-11 07:06:20

Trois that's what I thought, and then I read something that said that two blue eyed people could have a brown eyed child confused and I don't know where DH fits in as he has hazel eyes...

Bubbaluv Tue 11-Oct-11 07:06:45

Green is more recessive than blue from memory. Kind of like red hair.

CheerfulYank Tue 11-Oct-11 07:06:53

Is that her official title, Cother ? grin

CotherMuckingFunt Tue 11-Oct-11 07:10:25

<ahem> Yes. Most definitely.

CotherMuckingFunt Tue 11-Oct-11 07:12:02

And if she qualifies today she will be able to add the letters 'EOSWSE" after her name as well.

(Explainer Of Sarah's Weird Stripey Eyes)

It's a very important qualification!

Bubbaluv Tue 11-Oct-11 07:12:17

The recessive/dominant thing is the simple answer, but then some genes are linked to other inherited traits, so that can muddle things up and complicate the situation.
For example (this is made up as an illistration not a specific example) you could inherit a green eye gene and a brown eye gene. Green is recessive to brown so you should get brown BUT you inherit red hair which is linked to your green eye gene so you end up with red hair and green eyes.

So that is my understanding of how 2 blueys can make a brown.

EndoplasmicReticulum Tue 11-Oct-11 07:13:20

I teach this, the explanation we give year 9 is that brown is dominant, blue is recessive. CheerfulYank's husband may have brown eyes, but have one brown and one blue allele (type of gene) - so has passed the blue one on.

In reality it's more complicated than this, as suggested by CMF's mum.

Have a look at this:

PaschaTheSlasher Tue 11-Oct-11 07:13:29

Well now I'm intrigued. I have deep brown eyes, DH has blue. Boy has pale blue with a ring of golden amber in the centre. I often wonder if he's heading brown and will one day wake up changed. Can that happen?

Bubbaluv Tue 11-Oct-11 07:13:29

Cother - my family is full of stripy eyed people!

troisgarcons Tue 11-Oct-11 07:20:34

My uncle had one blue and one green eye.
no idea where he got the green one from - my mothers side is all blue eyes ....

Groovee Tue 11-Oct-11 07:20:57

In our family me and my 3 siblings have brown eyes. We've all got oldest daughters with blue eyes as we all had blue eyed partners. Our 2nd children all have the brown eyes. Everyone said when I had dd that she would have brown eyes and she's got her dad's eyes instead. Her brother has brown like me.

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