How did our son end up with *hazel* eyes?

[Ruffian]

I know that Mendelian genetics are quite a bit more complicated than the simple patterns I learned in biology 101, but this has thrown me for a loop. I have dark brown eyes, as do all members of my immediate family (my mother, father, and two sisters); DeathLlama has bright blue-grey eyes, like his mother (his father has brown eyes, and DL has no siblings).

We figured our little RuffLlama would likely have brown eyes, though there was a possibility of blue (my aunt, cousin, and grandmother have blue eyes). But I'm thrown off that our 4 1/2-month old son appears to have hazel eyes--that is, blue-grey with brown flecks, giving a forest green appearance from a distance. I didn't think hazel was a possible outcome. He actually looks like someone took my husband's eye color as a background, and sprinkled my eye color over top. I didn't think a "mix" was possible genetically.

This website predicted that there was a 72.7% chance our son's eyes would be brown, and 13.6% chance each that they could be green or blue. It's a pretty simple calculator--it doesn't take extended family into consideration--and it doesn't really help explain where RuffLlama's eye color came from.

FTR, I know eye color can change a lot the first year. I don't think his eyes will be brown, however; every child in my family born had obviously dark brown eyes by two months.

[hawksgirl]

I think you're the only here who can answer that...

[Ruffian]

Awwww, I can't ask this question and NOT post links to pics of our little cutie...

This pic shows off his eye color best, whereas this one shows how they usually look when not brightly lit by flash.

He is the cutest baby ever, y'all must admit.

[WhyNot]

The Medelian genetics for general eye-color are not "Brown" or "Blue", but "Brown" or "Not-Brown". Blue, hazel, green, yellow and purple are the possible "not brown" eye colors. The details of which of those colors your child's eyes will be is left up to other genetic and physiologic factors - the amount of lipids in the iris, among other things. So the chances of any of those other colors are included in the 13.6% - blue and hazel being by far the most common. (I've only known one true yellow and one true purple eyecolor personally.)

So it's perfectly possible his eye coulds stay hazel. Then again, they could still change. Only time will tell.

[Ruffian]

Well, the leftover 27.2% (it was 13.6% *each* for blue or green).

According to the site I linked, green is dominant and only blue is recessive, at least, that's what I'm assuming in the bbbb bbGb bbGG BbGb BBGb patterns. Brown just appears to be, erm, more dominant. Is that an accurate-ish assessment?

I'm also curious what other genetic factors affect eye color (lipids in the iris, perhaps?).

BTW, I remember reading ages ago thatPeter Cetera (lead singer of Chicago) has yellow eyes. Trippy. Wonder how the heck that comes along, genetically, and if the parents weren't freaking out about it just a little.

[John Mace]

Originally Posted by WhyNot

So it's perfectly possible his eye coulds stay hazel. Then again, they could still change. Only time will tell.

Yep, and good point made in that 2nd sentence.

You have brown eyes, but that doesn't tell you anything about your full genotype. You may very well have one of the many "not brown" alleles that is hidden phenotypically by one "brown" allele. The wikipedia article on eye color is pretty good, btw.

[InternetLegend]

Originally Posted by Ruffian

He is the cutest baby ever, y'all must admit.

I have to agree (I know this is GQ, but that is a factual statement).

[x_lenia_x]

maybe they'll change colour? i'm olive skinned and was born with black hair, but had bright blue eyes for quite a while until they turned black/brown.

friend of mine is mix-raced but when she was born she looked completely white for a couple of years.

babies are funny things )

[AskNott]

From Mendel's early work with peas, we drew a lot of general conclusions about dominant and recessive genes. Working with those generalities, many parents got into false accusations about a charming baby's father's identity.

Knowledge about genetics has gone through massive growth in the last few decades, and now we know that Mendel's rules only go so far. Determining human eye color, for example, is a lot more complicated than a Mendelian chart. There is no point in trying to find out GreatGramaLlama's eye color, or the mailman's. Just accept what you got, and don't try to explain it.

[Eve]

Any chance you had a quickie with Shirley Booth?

[Hari Seldon]

As was said, eye color is much more complicated than simple Mendelian genetics. I will give my family as an example. My eyes give the impression of being blue, but they have brown flecks, small and not many. My wife's are similar, but just enough more brown flecks to leave an overall impression of green. My father's were similar to mine, but my mother's were brown, although her father was a blue-eyed blond (and pure--so far as is known--Ashkenazai Jewish as were all of us). Of my three kids, one appears to have brown eyes (but the brown is anything but uniform and a close look shows that they are just brown enough to give that overall impression). My two boys both have nearly pure blue eyes.

hair color is just as bad and one of the boys is pale blond, while the other two are dark brown. I am dark brown and my wife is dirty blond.

For something more bizarre, it is perfectly possible, although rare, for two blood type O parents to have a type A or B (or much rarer, even AB) blood. However, everyone in my family whose blood type I know has type A.

[rocking chair]

from my own family i can say, yep, brown and blue creates hazel. now, when those hazels all married blues (strange that), we ended up with a range of grays and blues. some of them are changeable, going gray-er or blue-er with emotion, light, or apparel.

[Cerowyn]

Originally Posted by Eve

Any chance you had a quickie with Shirley Booth?

That would be quite a feat since Ruffian and Shirley Booth are both genetically XX. Well, not the quickie part, but the having-a-baby-as-a-result part.

[John Mace]

Originally Posted by Cerowyn

That would be quite a feat since Ruffian and Shirley Booth are both genetically XX. Well, not the quickie part, but the having-a-baby-as-a-result part.

I think the quicky part sounds like XXX!

[RetroVertigo]

Originally Posted by Hari Seldon

For something more bizarre, it is perfectly possible, although rare, for two blood type O parents to have a type A or B (or much rarer, even AB) blood. However, everyone in my family whose blood type I know has type A.

(I assumed you wanted to say "two blood type O parents to have a child with type A or B (or much rarer, even AB) blood. )
(bolding mine)

Is this possible? Correct me if I'm wrong but isn't type O blood a recessive trait? So if both parents have a genotype (aa), how does one pass along a dominant alelle to make type A, B, or AB possible?

[astro]

Hazel Eye Variations w/ pics

A hazel eye.Hazel is usually used to describe eyes that contain elements of both green eyes and brown eyes, in rare cases, also containing gray or blue, sometimes transitioning from green at the edges to brown around the pupil, and light brown. Hazel eyes often change color depending on what the person is wearing (i.e. if the person is wearing green or purple, the eyes appear mostly green). They are commonly found in middle European countries such as the middle of Russia, Belarus, Ukraine, south and middle of Poland, south and middle of Germany, north of France, Switzerland, north of Italy, Turkey, Slovenia and others.

Amber eyes
Amber eyes are often mistakenly referred to as "hazel." They have, however, a much stronger yellowish/golden and russet/coppery tint than hazel eyes and are not as common in humans. The golden tint appears at its brightest in direct lighting or sunlight, but turns into a golden green-brown in the shade or a coppery brown in candlelight. Amber eyes are also nicknamed "cat eyes

So how might something like hazel eyes work? No one knows for sure but I’ll discuss some possibilities. But before that, it is important to go into a little detail about eye color.

Brown, green and blue eye color comes from a pigment called melanin. Brown eyes have a lot of melanin in the iris, green eyes have less, and blue eyes have little or no pigment.

Two genes, bey2 and gey, work together to make brown, green, or blue eyes. Each gene comes in two versions or alleles.

One form of bey2 makes lots of melanin (and is usually referred to as B) while the other form makes only a little (b). One form of gey makes some melanin (G) while the other makes only a little (b).


One of his eyes has B in some
cells and only b in others
So how do you get eye color from all of this? If you have B you get brown eyes, G but no B, green eyes and if you only have b, then you get blue eyes.

Most likely, hazel eyes simply have more melanin than green eyes but less than brown eyes. There are lots of ways to get this level of melanin genetically.

It may be that hazel eyes are the result of genes different from gey and bey2. Something like hey for hazel. And maybe hey is a bit like bey2 and gey in that it comes in two forms—one that makes enough melanin for hazel eyes (H) and one that makes little or no melanin (b).

If this were true, the scheme for eye color would have to be changed. In the new scheme, you would have brown eyes if you had B, hazel eyes if you had H but not B, green eyes if you had G but not H or B and blue eyes if you only had b.

My gut tells me this probably isn’t the answer. Even though this sounds pretty complex, it seems like it wouldn’t be that much harder to tease out than green and brown eyes. So it is probably something else.

Another possibility is a variation on this theme. Maybe hazel eyes come from different versions of bey2 or gey. I said at the outset that there were two versions of each gene. But what if there were more? What if there were many versions that result in the various shades of color we see?

This is certainly plausible and some recent research suggests that this might be part of the story. But again, I’m just not sure. I would think the genetics again would be easy enough that it would have been figured out by now.

[BiblioCat]

Originally Posted by John Mace

Yep, and good point made in that 2nd sentence.

You have brown eyes, but that doesn't tell you anything about your full genotype. You may very well have one of the many "not brown" alleles that is hidden phenotypically by one "brown" allele. The wikipedia article on eye color is pretty good, btw.

I'm going to go read the wikipedia article, but this 'Brown' and "Not-Brown' thing is interesting. My husband and I both have brown eyes, and our son has blue eyes. Both of our mothers have blues eyes, so I always figured we both carried some ressesive blue-eyed gene that popped out for him. Is that what happened?

[Kalhoun]

Originally Posted by BiblioCat

I'm going to go read the wikipedia article, but this 'Brown' and "Not-Brown' thing is interesting. My husband and I both have brown eyes, and our son has blue eyes. Both of our mothers have blues eyes, so I always figured we both carried some ressesive blue-eyed gene that popped out for him. Is that what happened?

That's exactly what happened (as I remember it). If he marries a blue-eyed girl, they will have only blue-eyed children, because it takes blue/blue to get blue eyes. I hope I got that right.

I have a brown-eyed dad and a gray/hazel-eyed mom. I got green eyes out of the deal. Go figure.

[FormerMarineGuy]

My whole family that we can all recall have brown eyes (my mom, dad, grandparents on both side, etc, sister, brother) but I have hazel. I personally think my Mom was sleeping around.

[easy e]

Originally Posted by FormerMarineGuy

My whole family that we can all recall have brown eyes (my mom, dad, grandparents on both side, etc, sister, brother) but I have hazel. I personally think my Mom was sleeping around.

This can still be explained. I used the eye color calculator linked in the OP and it spit out that 5.5% of your parents' offspring could have green eyes. In astro's link about how hazel eyes might work, the author supposes that there's a moderator gene M that works on the green gene G to turn it into hazel. Since M has no effect on B (brown) or b (blue), it could hide in your ancestors' genomes for quite a while before showing up with you.

Of course, it could be that your mom was sleeping around, but your having hazel eyes doesn't definitively prove that.

Maybe I'm just defensive, as when I was in 5th grade another kid told me I had to be adopted because my parents had brown hair and brown eyes and I had blonde hair (which has darkened quite a bit since) and blue eyes.

[Rhiannon8404]

Well, my mother has brown eyes (her parents were brown/blue), my father has blue eyes (his parents are green/blue), and I have hazel eyes.

Suburban Plankton has blue eyes. His parent's are blue/blue. I don't know his grandparents colors.

Our son has dark brown. Definitely not hazel. I don't understand it.

[Rhiannon8404]

Well, my mother has brown eyes (her parents were brown/blue), my father has blue eyes (his parents are green/blue), and I have hazel eyes.

Suburban Plankton has blue eyes. His parent's are blue/blue. I don't know his grandparents colors.

Our son has dark brown. Definitely not hazel. I don't understand it.

[Sleel]

The quick and easy answer based on your kid's age, and the pictures you linked to, is that you actually have no idea what his eye color is yet. He's still so young that the pigments in his eye haven't really started to be produced at normal levels yet. You'll have a much better idea what his adult eye color might be when he's about a year old, four months is way too early to tell how they'll develop.

Even after the one-year mark his eyes might continue to change. I had bright blue eyes until I hit puberty. Over the next few years they faded a bit to a blue-grey color. Then bits of green started to creep in. Now, at age 32 (damn birthdays keep sneaking up on me) I have mostly blue-grey eyes with green flecks, a color combination that makes them a bit chameleon-like. Depending on what I wear they can look very green to almost colorless grey. If you compared a picture of my eyes at age 2 to one taken right now at age 32 you wouldn't think they were the same person's eyes.