Thread: Eye color inheritance

I tried googling this but failed :P

If 1 parent has blue eyes and 1 brown eyes it is to my understanding that the brown color is dominant.

Is there a statistical flat % chanse to the color of the offspring or is it random with just a higher probability of getting brown?

Im dating a girl with brown eyes at the moment and i have blue eyes myself, but if i ever have children i want them to have blue eyes. So im wondering, hypothetically speaking - if i have 10 children is there any chanse to calculate the number who will get blue eyes and brown eyes or is that purely genetic gambling based far back in both our family trees? How complicated is it really?

Inheritance of eye color is quite complicated and not quite understood. I don't think all the genes involved are known yet. Blue and brown are best studied and can be predicted quite well, but not perfectly.

Anyway, I don't know the answer. But for fun you could play around with this eye colour calculator.

Like Zwirko said, there are a lot of genes involved.

Although, if she's from an ethnic group where blue eye genes are highly uncommon, like East Asian. The chances of you having blue eyed children is near 0 I think.

If some of her parents or siblings have blue eyes you'll have a better chance, obviously.

I once knew a guy who was half Fijian Melanesian (very like an African) and half European. He had a substantially dark skin. He also had bright blue eyes. This is not a story. It is true.

Anyone like to guess why?

Originally Posted by skeptic

I once knew a guy who was half Fijian Melanesian (very like an African) and half European. He had a substantially dark skin. He also had bright blue eyes. This is not a story. It is true.

Anyone like to guess why?

As far as I'm aware the only blue eye mutation present in humanity is of Caucasian origin. Blue eye colour inheritance is close to mimicking recessive inheritance, but it's not quite the same. There is a chance the guy had some European ancestry on his Fijian side. A recessive blue eye gene could be carried through several generations without producing blue eyes, although it is statistically unlikely. Also, apart from the gene that causes low melanin production in the iris (which causes blue eyes) there are other genes apparently involved that are less well understood and could maybe produce blue eyes even though someone only carries one blue eye allele of OCA2.

Tired and sleepy

Think again. The explanation is a lot simpler than that and requires only basic Mendelian genetics.

Suggest you re-read. All the information you need is in my post.

uh about mendelian genetic youre right so i guess its about how lucky you are to get that right, cause from what i get here blue eyes is recessive and its need a long road to get recessive meet the recessive so it will goes hide in your children, so if you have 10 children thats not mean the last children will get your blue eyes maybe it will appear on your grandchildren, but if you lucky your last child will get your blue eyes

Originally Posted by skeptic

Tired and sleepy

Think again. The explanation is a lot simpler than that and requires only basic Mendelian genetics.

Suggest you re-read. All the information you need is in my post.

I didn't think you were telling a riddle, each of the parents was half European I'm guessing.

Tired and sleepy.

You are correct. I actually met this guys parents before I met him. Both half Fijian and half European. That should be all the clue anyone needs to trace simple Mendelian inheritance of the blue eye trait.

It's a bit like another old conundrum I once heard.

Young guy driving too fast has a serious accident. Ambulance arrives and whisks him off to hospital. Wheeled into the theatre for emergency surgery. The surgeon walks in, takes one look and says : "My God. My son!"

If the surgeon is not his father, what is the relationship?

His mother, but that is a very old one.

Tired and sleepy.
Correct. It is a very old one, but it is still amazing how many people fail to get it. I once has the situation where a feminist could not get it. When I explained it to her, she was utterly devastated at her own assumption.

The point is that we all tend to rely on shakey assumptions in our thinking. Lots of puzzles are based on the inability to shake them off.

Have you tried the "nine dots" puzzle?
Draw a matrix of nine dots. Three rows, each with 3 dots. Perfectly symmetrical.

Now see if you can take your pen, and draw four lines to connect all nine dots. You are not allowed to take your pen off the page once you begin, so all four lines must connect to each other.

Originally Posted by Zwirko

Inheritance of eye color is quite complicated and not quite understood. I don't think all the genes involved are known yet. Blue and brown are best studied and can be predicted quite well, but not perfectly.

Anyway, I don't know the answer. But for fun you could play around with this eye colour calculator.

Interesting link.

I guess I cannot have blue eyed kids because of the green.

My father has blue eyes, by mother brown. I have a sister with blue eyes, but mine are green. I can only have green or brown eyed children. Both my daughters have brown eyes.

Originally Posted by Raziell

I tried googling this but failed :P

If 1 parent has blue eyes and 1 brown eyes it is to my understanding that the brown color is dominant.

Is there a statistical flat % chanse to the color of the offspring or is it random with just a higher probability of getting brown?

Im dating a girl with brown eyes at the moment and i have blue eyes myself, but if i ever have children i want them to have blue eyes. So im wondering, hypothetically speaking - if i have 10 children is there any chanse to calculate the number who will get blue eyes and brown eyes or is that purely genetic gambling based far back in both our family trees? How complicated is it really?

The way I understand it. Take for example that B is a gene for dark eyes, and b is a gene for bright eyes. For a person to have bright eyes you need to get that "b" gene from both of your parents. You have blue eyes, that is "bb", your mate has brown eyes, so he/she can either have "BB" or "Bb" genes. The first case, means that both her genes are for brown eyes, so your children can't have blue eyes. But in the other case, she has one gene for blue eyes, and therefore there is a 1:4 chance for your child to have blue eyes.
Now, how do you see if she has "BB" or "Bb"? Watch for her parents. If either of her parents has blue eyes, there you go, she has "Bb". If not, go further through the family and you'll see.

Originally Posted by Wild Cobra

Originally Posted by Zwirko

Inheritance of eye color is quite complicated and not quite understood. I don't think all the genes involved are known yet. Blue and brown are best studied and can be predicted quite well, but not perfectly.

Anyway, I don't know the answer. But for fun you could play around with this eye colour calculator.

Interesting link.

I guess I cannot have blue eyed kids because of the green.

My father has blue eyes, by mother brown. I have a sister with blue eyes, but mine are green. I can only have green or brown eyed children. Both my daughters have brown eyes.

Nonsense. If your father has blue eyes, you can have blue eyed children.

Originally Posted by JennLonhon

Originally Posted by Raziell

I tried googling this but failed :P

If 1 parent has blue eyes and 1 brown eyes it is to my understanding that the brown color is dominant.

Is there a statistical flat % chanse to the color of the offspring or is it random with just a higher probability of getting brown?

Im dating a girl with brown eyes at the moment and i have blue eyes myself, but if i ever have children i want them to have blue eyes. So im wondering, hypothetically speaking - if i have 10 children is there any chanse to calculate the number who will get blue eyes and brown eyes or is that purely genetic gambling based far back in both our family trees? How complicated is it really?

The way I understand it. Take for example that B is a gene for dark eyes, and b is a gene for bright eyes. For a person to have bright eyes you need to get that "b" gene from both of your parents. You have blue eyes, that is "bb", your mate has brown eyes, so he/she can either have "BB" or "Bb" genes. The first case, means that both her genes are for brown eyes, so your children can't have blue eyes. But in the other case, she has one gene for blue eyes, and therefore there is a 1:4 chance for your child to have blue eyes.
Now, how do you see if she has "BB" or "Bb"? Watch for her parents. If either of her parents has blue eyes, there you go, she has "Bb". If not, go further through the family and you'll see.

To repeat though, with blue and brown eyes the relationship follows nearly Mendelian patterns, but for most of the other eye colours it's harder to accurately predict. Should also consider the fact that not all blue eyed and brown eyed people have identical shades.

More importantly, it does not matter a damn.

If your girlfriend has brown eyes and you blue, and you want to have children with blue eyes, at best each child you might have with her may have a 50:50 chance of having blue eyes. Much more importantly though is for you to dump this ridiculous preference. Your children are precious, and whether they have brown or blue eyes is about as trivial as any consideration I have ever heard.

Basically, if you are sufficiently keen on your girlfriend, and she is keen on you, get married and let your kids be what they are. Change yourself, not your kids.

Originally Posted by skeptic

More importantly, it does not matter a damn.

If your girlfriend has brown eyes and you blue, and you want to have children with blue eyes, at best each child you might have with her may have a 50:50 chance of having blue eyes. Much more importantly though is for you to dump this ridiculous preference. Your children are precious, and whether they have brown or blue eyes is about as trivial as any consideration I have ever heard.

Basically, if you are sufficiently keen on your girlfriend, and she is keen on you, get married and let your kids be what they are. Change yourself, not your kids.

Like I said, it's not 50-50, it's 1:4 chances, but true, if you love someone, it doesn't really matter does it? On the other hand, I'd love to have blue eyed children =))

Originally Posted by Twit of wit

Originally Posted by Wild Cobra

Originally Posted by Zwirko

Inheritance of eye color is quite complicated and not quite understood. I don't think all the genes involved are known yet. Blue and brown are best studied and can be predicted quite well, but not perfectly.

Anyway, I don't know the answer. But for fun you could play around with this eye colour calculator.

Interesting link.

I guess I cannot have blue eyed kids because of the green.

My father has blue eyes, by mother brown. I have a sister with blue eyes, but mine are green. I can only have green or brown eyed children. Both my daughters have brown eyes.

Nonsense. If your father has blue eyes, you can have blue eyed children.

That's what I thought, but the calculator said otherwise.

So, how is it that a child's eyes can change color? For example when she is hungry her eye will turn brown/red or when she is really happy her eyes will turn bright green.

Originally Posted by Wild Cobra

Originally Posted by Twit of wit

Nonsense. If your father has blue eyes, you can have blue eyed children.

That's what I thought, but the calculator said otherwise.

I guess it's because your wife can't have blue eyed children.

How can it be simple mendelian inheritance if the color blue is determined by several genes.

A prediction model based on multinomial logistic regression constructed in the model-building set (n = 3804, 61.7%) using 24 SNPs from eight genes revealed excellent accuracy for predicting blue and brown eye color in the model-verification set (n = 2364, 38.3%) based on five parameters (Table 1). 13 SNPs were removed because of strong linkage disequilibrium with other markers in this set (Supplemental Data). Considering the area under the receiver characteristic operating curves (AUC) as an overall measure for prediction accuracy, whereby a completely accurate prediction is obtained at an AUC of 1, we obtained very high values for brown eyes at 0.93 and for blue eyes at 0.91. The prediction of intermediate color was less accurate with an AUC of 0.73. Predicting eye color using four alternative models yielded similar results (Supplemental Data). The lower prediction accuracy for intermediate eye color may be explained by unidentified associated SNPs as well as imprecise phenotype characterization; future investigations with more information on subtle phenotype characterization are warranted.

they wouldn't need prediction models if it was all determined by simple mendelian inheritance.

Originally Posted by Twit of wit

Originally Posted by Wild Cobra

Originally Posted by Twit of wit

Nonsense. If your father has blue eyes, you can have blue eyed children.

That's what I thought, but the calculator said otherwise.

I guess it's because your wife can't have blue eyed children.

That would mean knowing that the gene for blue is non-existent in my wife. The calculator didn't eliminate that I don't think. I just redid it with her having green and blue eyed siblings. Same thing. Either the calculator is wrong, or our gene mix cannot produce blue.

People could have cheated their partners in your lineage. That would throw off any calculator because it doesn't incorporate lies.

Now I'm confused. Can a person with green eyes carry recessive brown?