Can someone explain chances of 4 kids with blue eyes when one parent is brown eyed?

[Korner]

Dsister (blue eyes) has 4 kids with BIL (very dark brown eyes almost black). All 4 kids (7 - 3 yo) have bright blue eyes.

BIL is Sikh Punjabi. Apparently has no history of blue eyes but says some second cousins have green eyes - not common but not unusual. My family all pretty much have blue eyes.

This has to be an anomaly. Just curious as the discussion came up at baby group today. Learned that it should only really be 50% likelihood of blue eyes if one parent has brown eyes and the other
blue.

I have one of each (brown and blue) despite DH being green eyed. I’m also blue eyed.
Genes are very interesting!

I've got 4 boys.
One blue eyed, 3 brown.
I've got blue eyes, my husband has brown.

I'm also one of 4.
All of us have blue eyes, my mam has blue eyes and my dad has brown

The likelihood is 50/50 each and every time, so each child has a 50/50 chance of blue eyes.

I asked this. Apparently the BB Bb bb recessive dominant etc. is the equivalent of telling a GCSE kid that a cell is a nucleus, cytoplasm and a cell membrane.

In actual fact that’s a complete lie. There’s a lot of shit in a cell. And apparently eye colour is way more complicated than that.

My parents are (dusky grey) blue and green also. My sisters brown and I am dark blue with an orange strike through one.

My partners almond brown. My little boys eyes are almost jet black.

I have blue eyes husband has brown we have 4 kids 3 with blue eyes but all different types of blue and one with brown eyes..

Your BIL has a green/ blue eyes gene and one dark brown.
Your DS two blue eyes genes.
Chances are then 50% for blue and 50% dark brown for each child.
They just happened to have all kids in the blue lot.

I’m ginger with brown eyes, DH is brunette with blue eyes.
We have 1 brunette with hazel eyes, 1 brunette with blue eyes and 1 blond with grey/blue eyes.

Brown, hazel eyes are pigments in the iris.
But blue/ green/ grey have almost no pigment. The colour comes mostly from how the iris reflects light around.
The pigment is actually melanin, so brown in itself.
We all know people whose eye colour changes with the lighting conditions.
Also, it is common for people that genetically should have green eyes to appear brown, or even change colour through life, have a green/ brown combination in the eyes.

Perfectly possible. My DD has blue eyes - she is white / Asian. DS has brown eyes.

No, I know. But it’s a simple way to explain why someone with brown eyes might carry a blue gene.

Me brown eyes , DH blue, both sons blue , I also thought brown would ‘win’

Punjabi people have mixed heritage as there have been various groups in the region, notably Alexander the Great conquered the region (and his army seem to have left their genetic heritage!)

I am Punjabi myself and have a large family (many are very white & green eyed despite 100% Punjabi origins).

I also know many mixed Punjabi/White families. Blue eyes and very white skin not very unusual for mixed Punjabi/Caucasian kids (4 in same family less usual) : sometimes this changes as kids grow older too

Genetics are a crazy thing. My aunt and uncle are both average heights (5ft 6 and 5ft 10) with straight brown hair and green eyes.
Child one: 6ft 5 brown hair, green eyes, child two: 6ft curly ginger hair, blue eyes,
Child three: 5ft 1 blond hair, green eyes
Child four: 5ft 5 Black hair, brown eyes
Child five: 6ft 2 curly blond-brown hair, brown eyes.

We both have brown eyes, both DDs have blue eyes. I was very surprised by this x

If one parent has blue eyes then yes it is 50/50.

The odds of any one child having blue eyes are also completely independent from the eye colours of the other children. Each child has the same odds.

2 of my nephew's were born with blue eyes but within a week or 2 their eyes had somehow turned to brown. My sister said one DC went to sleep with blue eyes one morning and by dinner time his eyes were light brown. The next day they had turned darker brown. It's amazing.

https://www.allaboutvision.com/eye-care/eye-anatomy/eye-color-genetics/

My husband had blue eyes, blond hair. I have brown wavy hair, hazel eyes. All 4 of our children have brown wavy hair, hazel eyes. Granddaughters also brown wavy hair, hazel eyes. My genes are more dominant.

The dominant-recessive model of eye genetics is now very outdated. More than 16 genes can affect eye colour, including occasionally randomly switching off of the relevant genes for brown eyes (thus resulting in blue eyes) even when neither parent has any alleles for blue at all.

It’s all quite fascinating. I have very blue eyes; DD’s dad has hazel. DD had very blue eyes up until she was about eight years old, and now they have turned very green! (My mother has green eyes, interestingly.)

Even if there is no tendency for blue in the genes a child inherits, the genes that control for melanin in the eye can sometimes, as with any genetic mutation, quite randomly be switched off, resulting in a child without melanin (and thus blue or light eyes).

My DD has blue eyes and red hair, what are the chances of this combination?! This seems unique?

No one in my dh family has brown eyes except his brother who has brown . Going back to aunts, uncles grandparents - all blue . We don’t think he and his brother have the same father .
Are we right?

Oh and I have a brown streak in one of my eyes (otherwise very blue!) - caused by a random mutation in the melanin-producing cells just in that patch. Neither of my parents have any brown in their eyes (green and blue). Flecks or random patches of brown or yellow in blue eyes are also very common.

Very common in redheads/those of Celtic heritage, no? It’s more unusual IME for redheads to have brown eyes, at least in the U.K. and Ireland.

Both dc have sky blue eyes.

I have blue eyes and DH has very dark brown eyes, almost black.

The whole extended family did an ancestry dna test a while back for fun (so the dc aren't the milkmans 🤣). It turns out that DH actually has some iceland/Norway dna in there somewhere!

My DM was adamant that my dc would have blue eyes, DH was most disgruntled that he lost the bet twice.