How are the J&K+8 kids genetically possible?

AnneUCSB · May 2009

Correct me if I am wrong, but doesn't Kate have blue eyes and John has greenish eyes (they are not straight brown) but all the kids have dark brown eyes??? Um, if neither parent carries the gene for brown eyes (which they don't or else one of them would actually have brown eyes), how are their kids genetically possible? I'm no genetic counselor, so if you are, please educate me. Thanks

ithadtobeyou · May 2009

Both parents carry the gene for brown eyes. But both parents themselves had the recessive genes for green and blue eyes and got those. Doesn't mean they can't have brown eyed kids.

My mom has blue and my dad green, and my sister has brown. So it's totally possible. Brown eyes are dominant, so if both parents carry brown genes the kids are likely to get brown. That's my understanding.

firefightersgal · May 2009

DH and I both have blue eyes--Nora has hazel-ish eyes. They are definitely not blue or even green. I thought we'd have a blue-eyed kid, for sure. We both have a lot of family with brown and/or hazel eyes, so I suppose a stray gene snuck in there somewhere.

AnneUCSB · May 2009

ithadtobeyou:
Both parents carry the gene for brown eyes. But both parents themselves had the recessive genes for green and blue eyes and got those. Doesn't mean they can't have brown eyed kids.
My mom has blue and my dad green, and my sister has brown. So it's totally possible. Brown eyes are dominant, so if both parents carry brown genes the kids are likely to get brown. That's my understanding.

Ok, so how I understand it is that if you carry the gene for brown eyes, you will HAVE brown eyes because it is dominant. If you have blue eyes, you can only carry the gene for blue (or green which is a mutation of blue). So, that said, J and K only carry recessive genes (blue/green) so how did they give brown?

DH has brown and I have blue/green and our boys both have blue, so I get that (DH has one gene for brown and one gene for blue but shows brown because that is dominant). KWIM???

emiliemadison · May 2009

Two non-brown eyed parents can have brown eyed children. You can have a brown eyed gene yourself and not be brown eyed, so if your partner also has a brown eyed gene (even if they dont have brown eyes) then you can most certainly have brown eyed children.

Halo79RN · May 2009

I think it has something to do with melanin production in the iris.. I don't think it's as straight forward as a general bio class used to explain. I remember reading something a year or two ago on the topic and there's was new or newish info on the topic. I'll have to search around for it though. I think it was a The New Yorker article.

luckyluvr · May 2009

Jon's "eyes" are likely contacts. Most Asian people have dark brown eyes, and whenever there is 1 brown alele (sp?), brown will dominate. My grandmother had blue, my grandfather had hazel...5 of their kids have blue, my mom has brown. In their case it's the hazel throwing them off. Both my parents have brown, but my sister has blue, so they each carry a recessive blue alele.

ithadtobeyou · May 2009

No, you can CARRY brown and not get brown eyes. We all have both dominant and recessive genes. What gets played out in us is the result of our genetics..and sometimes you get a double recessive (recessive from both mom and dad) or you get a dominant (that only had to come from grandpa way back). Genes go back further than mom and dad. That's why some people look more like a grandparent or great uncle, etc.

DandelionMom · May 2009

Eye color is one of those traits that involve several genes so it isn't always as simple as dominant and recessive.

femmegem · May 2009

https://www.thetech.org/genetics/ask.php?id=2

Apparently it's not as simple as having two genes, one dominant over the other. I didn't read this carefully so I don't really get it.

emiliemadison · May 2009

ithadtobeyou:
No, you can CARRY brown and not get brown eyes. We all have both dominant and recessive genes. What gets played out in us is the result of our genetics..and sometimes you get a double recessive (recessive from both mom and dad) or you get a dominant (that only had to come from grandpa way back). Genes go back further than mom and dad. That's why some people look more like a grandparent or great uncle, etc.

Exactly

AnneUCSB · May 2009

emiliemadison:
ithadtobeyou:
No, you can CARRY brown and not get brown eyes. We all have bothdominant and recessive genes. What gets played out in us is the resultof our genetics..and sometimes you get a double recessive (recessivefrom both mom and dad) or you get a dominant (that only had to comefrom grandpa way back). Genes go back further than mom and dad. That'swhy some people look more like a grandparent or great uncle, etc.
Exactly

Well, you learn something new everyday, huh? I've never known a family IRL who had two blue or green-eyed parents and had brown-eyed kids. Hmmm. Interesting

Halo79RN · May 2009

the thing of it is, there are 2 chromosomes (so 2 pairs of genes, I think) that determine eye color... so it's like brown vs blue on one set and hazel/green vs light on the other.. and the combo of thos combos, determines eye color. it's really very confusing. but I agree with pp, I bet Jon's color is contact related.

emiliemadison · May 2009

Genetics is fascinating! Until just a few years ago, "they" still weren't completely confident about the dominant/recessive combination of alleles and their implications in eye color. There was a belief that two blue eyed parents could not genetically produce a brown eyed child because, as you had stated, the belief was that if either of the parents had the brown allele, they themselves would have brown eyes. But, this has been disproven, and it's now understood that two blue eyed parents can, indeed, have a brown eyed child. Amazing stuff!

AnneUCSB · May 2009

emiliemadison:
Genetics is fascinating! Until just a few years ago, "they" still weren't completely confident about the dominant/recessive combination of alleles and their implications in eye color. There was a belief that two blue eyed parents could not genetically produce a brown eyed child because, as you had stated, the belief was that if either of the parents had the brown allele, they themselves would have brown eyes. But, this has been disproven, and it's now understood that two blue eyed parents can, indeed, have a brown eyed child. Amazing stuff!

Seeing as how it's been over 10 yrs since I was in college, I was only taught Mendelian Genetics. Times have changed, and now I have been my knowledge base has been updated. Look how education the Nest can be

kylara111 · May 2009

As the PPs said its not that simple.

You can see me in my sig. I'm hispanic with brown eyes. I have a couple of cousins with light eyes, but not my parents or grandparents. DH has blue. BOTH my girls have blue eyes. I doubted it was possible and thought #1 was a fluke. Then, #2 ended up with blue as well.

magnoliablossom · May 2009

kylara111:

As the PPs said its not that simple.

You can see me in my sig. I'm hispanic with brown eyes. I have a couple of cousins with light eyes, but not my parents or grandparents. DH has blue. BOTH my girls have blue eyes. I doubted it was possible and thought #1 was a fluke. Then, #2 ended up with blue as well.

DH has black curly hair with brown eyes. I am blonde with green/hazel eyes.

C has sandy blonde hair with hazel eyes and A is a strawberry blonde with blue eyes.

I had always thought, and silently hoped for, children with black/brunette hair and green eyes. C'est la vie!

Littlejen22 · May 2009

I learned it the same way you did..that blue was recessive and you had to have 2 blue genes to have blue eyes and that you only had two genes so you could only pass that on BUT apparently we were taught wrong. Not sure if they just simplified it for us or if they just understand a lot more now.

https://www.docshop.com/2008/01/04/what-color-will-my-babys-eyes-be/

Littlejen22 · May 2009

According to what I just posted green plus blue means no chance of brown...INTERESTING!

AggieCouple · May 2009

Here is what I know from my biochemistry degree background. ?No, the brown eye gene is dominant so in MOST cases, having a single brown eye gene WILL result in brown eyes. ?There is an anomaly, however, where a light-eyed gene can be dominant in some family lines. ?It's very rare but it happens. ?All genes affect one another, and when the chromosome carries another set of genes, that may or may not have anything to do with eye color, it can override the dominance of brown eyes. ?Whatever the case may be for the J+K kids, eye color is not considered a "quantity" gene (like height, where the parents contribute a a discrete "amount" of height, so two very tall parents can have a very short child or any combination), but a pretty straight forward Mendelian gene.

Here is what I know from being Asian ;o) I thought John was not 100% Asian? ?If he is, it is highly unlikely??(almost impossible) for him to have non-brown eyes. ?I agree that must be colored contacts.

?BUT, I am Asian, I have dark brown eyes,??my husband has grey/hazel/green eyes. ?My daughter has medium brown eyes, and my son has light brown eyes that look hazel in certain lighting. ?

KoriBrett · May 2009

As long as one person on each side somewhere had brown eyes at some point, even if the parents don't, the kids still can have them. They both have to be a carrier, but don't have to show it.

Brown eyes are dominant over the rest, too, so in the blender/mix of things, brown is more likely to happen than the other colors.

AggieCouple · May 2009

kylara111:
As the PPs said its not that simple.
You can see me in my sig.? I'm hispanic with brown eyes.??I have a couple of cousins with light eyes, but not my parents or grandparents.? DH has blue.? BOTH my girls have blue eyes.? I doubted it was possible and thought #1 was a fluke.? Then, #2 ended up with blue as well.

?Your case actually makes perfect sense and follows Mendelian rules. ?You have brown eyes because you have one dominant brown-eyed gene and one recessive gene for light-colored eyes. ?This is confirmed by the fact that your grandparents passed on a recessive light colored gene to your cousins, and also to your parent, which he/she passed on to you, while the other parent contributed the dark-eyed gene. ?You passed on the recessive gene to your children, and your husband gave one of his 2 recessive blue-eyed genes.?

AggieCouple · May 2009

KoriBrett:
As long as one person on each side somewhere had brown eyes at some point, even if the parents don't, the kids still can have them.? They both have to be a carrier, but don't have to show it.?
Brown eyes are dominant over the rest, too, so in the blender/mix of things, brown is more likely to happen than the other colors.

IF John has light-colored eyes, and if their blood line isn't a fluke of nature (dominant blue eyes), it would be impossible for either John or Kate to pass on brown-eyed genes, because neither would have any brown-eyed genes. ?If "one person one each side somewhere had brown eyes" then that brown-eyed gene HAS to show a trail, because wherever it showed up to be passed to the next generation, that person would be brown-eyed. ?

hopefulmom · May 2009

I don't know a thing about genetics but both of my parents had brown eyes. My sister and I got brown eyes but both of my brothers got BLUE eyes. Not fair...I was always jealous!

Chrisy-Wyobride · May 2009

My bet is on colored contacts for Jon...LOL! That being said both my kids are blond & DH is a redhead & I have always been brunette--so they are weird to me--LOL!

Disneygeek77 · May 2009

I think he wears contacts. I have wondered the same thing and than in one episode where they show Jon and Kate when they were younger ( pre marriage and even pics of their wedding ) I could have sworn that he had brown eyes.