Eye Color Inheritance

[Ánleifr]

Can someone help me understand where eye color inheritance comes from? For example, in this scenario where does my eye color come from?

Paternal Grandfather = brown eyes
Paternal Grandmother = blue eyes
Maternal Grandfather = blue eyes
Maternal Grandmother = brown eyes
Father = brown eyes
Mother = light eyes

Thanks!

[Geminus]

Let's call the genes for blue eyes "bl" and the gene for brown eyes "BR". Then you have to differ between genotype and phenotype.
In your genotype you have two instances of these genes (one from your father and one from your mother). You can have for example "bl bl" or "BR bl" or "BR BR". The genes for brown eyes are dominant, so when you've got at least one "BR" in your genotype your phenotype will be also "BR", so you've got brown eyes. Only when your genotype is "bl bl" you phenotype will be also "bl" and you have blue eyes.

But it's important that you can give on both genes from your genotype to your children. So if you've got the genotype "BR bl" and your wife "BR BR" any combination of this genes is possible (that would be "BR BR" and "BR bl")

In your example you can determine the genotype of your parents:
Father: "BR bl"
Mother: "bl bl"

So you can either have the genotype "BR bl" or "bl bl", which means you could have either brown or blue eyes.

[Ánleifr]

Let's call the genes for blue eyes "bl" and the gene for brown eyes "BR". Then you have to differ between genotype and phenotype.
In your genotype you have two instances of these genes (one from your father and one from your mother). You can have for example "bl bl" or "BR bl" or "BR BR". The genes for brown eyes are dominant, so when you've got at least one "BR" in your genotype your phenotype will be also "BR", so you've got brown eyes. Only when your genotype is "bl bl" you phenotype will be also "bl" and you have blue eyes.

But it's important that you can give on both genes from your genotype to your children. So if you've got the genotype "BR bl" and your wife "BR BR" any combination of this genes is possible (that would be "BR BR" and "BR bl")

In your example you can determine the genotype of your parents:
Father: "BR bl"
Mother: "bl bl"

So you can either have the genotype "BR bl" or "bl bl", which means you could have either brown or blue eyes.

yes, I have blue and my sister has brown. I was just wondering where I received mine from.

[Viljuska]

http://genetics.thetech.org/online-exhibits/what-color-eyes-will-your-children-have

[cmd_]

yes, I have blue and my sister has brown. I was just wondering where I received mine from.Blue-eyed couple will always have a 100% chance getting a blue-eyed chilled.
Brown-eyed couple will have a high chance on getting a brown-eyed child but there is still a chance it will have green or blue eyes.

Don't ask me why. That's just how it works. Blue eyes have to pigmentation afaik.

[Damião de Góis]

From my experience it's random. My case:

Paternal grandfather - Brown
Paternal grandmother - Brown

Maternal grandfather - Blue
Maternal grandfather - Brown

Father - Brown
Mother - Green

Me - Green

[Slycooper]

Mine is

Paternal Grandfather - Blue
Paternal Grandmother - Brown

Maternal Grandfather - Brown
Maternal Grandmother - Brown

Father - Green
Mother - Brown
Me - Hazel Green

[Geminus]

From my experience it's random.

Probably it can't be wholly explained through a Mendelian scheme, as Green seems to exist as mixture between green and blue etc.
But in general brown or darker eye colors are dominant to lighter ones.

[Lumi]

There is a thing called the milk-man gene, y'know.
The milk-man gene basically is the name given to fluke genes.
For example. Both your parents have brown eyes, but you end up with blue eyes.
Two Dominant genes can make a recessive gene.

My Paternal Grandparents both have blue eyes, so therefore my Dad does too. My Uncle, however, has brown eyes.

My Maternal Grandparents, my Gran had brown eyes, and my Grandfather had blue. My Mum ended up with brown eyes.

I have blue eyes, and my cousin has blue, because his Mum is blue eyed, and yet my Uncle has brown eyes.

My wee sister has blue eyes like my Dad.

Fluke genes happen.
I knew a girl whose parents were both blue eyed. She ended up with (I kid you not) violet eyes.

Genetics aren't as simple as you may think. Weird things happen with genetics.

[aimar]

Mine is

Paternal grandfather - green
Paternal grandmother - green

Maternal grandmother - green
Maternal grandfather - Brown

Father - green
mother - brown

Me and my sister - brown

[Foxy]

Blue-eyed couple will always have a 100% chance getting a blue-eyed chilled.
Brown-eyed couple will have a high chance on getting a brown-eyed child but there is still a chance it will have green or blue eyes.

Don't ask me why. That's just how it works. Blue eyes have to pigmentation afaik.

Not true, I know a couple of blue eyed elders whose second son is brown eyed, although the other two are blue eyed. How is it possible? (The son looks identical to the father so exclude what you are thinking...).

[aimar]

my father has 7 brothers/sisters, all green eyed, I have 15 cousins from that side of the familly, 13 brown eyed, 1 green eyed and 1 blue eyed

[Foxy]

My line is:

- maternal grandmother: green eyes
- maternal grandfather: brown eyes

- paternal grandmother: green eyes
- paternal grandfather: blue eyes

- mother: brown eyes
- father: brown-hazel eyes (unscientific)

- me: brown eyes (in theory I had to have green eyes).

[Foxy]

Or also my bf line:

- maternal grandmom: blue eyes
- maternal grandfather: blue eyes

- paternal grandmother: brown eyes
- paternal grandfather: blue eyes

- mom: blue eyes
- dad: brown eyes (light brown, almost hazel)

- brother: dark brown eyes
- he: hazel-green eyes.

A COUPLE OF BLUE EYED PEOPLE CAN HAVE BROWN/HAZEL EYED CHILDREN.

[Graham]

- Maternal grandmother: Grey-Blue
- Maternal grandfather: Green

- Paternal grandmother: Hazel
- Paternal grandfather: Brown?

- Mother: Green
- Father: Blue-Green

- Me: Hazel-green,brown.
- brother: Blue

Not much the same.

[Lumi]

Not true, I know a couple of blue eyed elders whose second son is brown eyed, although the other two are blue eyed. How is it possible? (The son looks identical to the father so exclude what you are thinking...).


Fluke genetics.
Simple answer.

[Peyrol]

Paternal grandfather - brown
Paternal grandmother - brown

Maternal grandmother - amber
Maternal grandfather - blue

Father - brown
mother - green/grey

Me - brown


Totally illogical in the mom side...

[Patches]

-Maternal grandmother: Brown
-Maternal grandfather: Hazel

-Paternal grandmother: Brown/Hazel?
-Paternal grandfather: Blue

-Father: Brown
-Mother: Green

-Me: Blue

[Foxy]

Paternal grandfather - brown
Paternal grandmother - brown

Maternal grandmother - amber
Maternal grandfather - blue

Father - brown
mother - green/grey

Me - brown


Totally illogical in the mom side...

I have noticed that only in Italians eye colour seems to go by a fluke, the other people here have scientific lines. Can this happen because we are more mixed? An other case in my family:

father: blonde hair/blue eyes
mother: blonde hair/ blue-grey eyes
son: black hair/ brown eyes (how is it possible?)
brother: blonde hair/ light eyes (don't remember the right colour)

[Corvus]

Mother: Brown hair/green eyes
Father: Brown hair/brown eyes

Me: Brown eyes

[Peyrol]

I have noticed that only in Italians eye colour seems to go by a fluke, the other people here have scientific lines. Can this happen because we are more mixed? An other case in my family:

father: blonde hair/blue eyes
mother: blonde hair/ blue-grey eyes
son: black hair/ brown eyes (how is it possible?)
brother: blonde hair/ light eyes (don't remember the right colour)

I noticed this trend too.

Probabily, as population, we've a lot of recessive genes which often
appears after generations.

[Geminus]

I noticed this trend too.

Probabily, as population, we've a lot of recessive genes which often
appears after generations.

Europid populations very often have recessive light genes, even in parts of Iran or Arabia people sometimes have light eyes (much more often compared to Asian people)
To me it seems that in Germany almost everyone has got at least recessive genes for light eyes, also two of my grandparents had brown eyes, but nevertheless I got light eyes ;)