Calling all geneticists! Help me understand the way my mixed race child looks

[Feelingchipper]

We are a mixed South East Asian-Caucasian (European rather than English) family. My first child looks standard mixed race. My 2nd child has brown-blonde hair and blue eyes, which are no longer the dark blue of newborn babies. 2nd child is past the 6 month point and although she may lose the blonde hair and blue eyes soon enough, it still seems very surprising! On my side of the family, babies are usually born with brown eyes and black hair or, less commonly, grey eyes (for a short period) and very dark brown hair. There are no non-South East Asians in my family for as far back as anyone can remember, at least a century. However, there are some members of my family on both my parents' sides with lighter colouring (lighter brown skin, lighter brown eyes, very dark brown hair rather than black), which could indicate some non-local ancestry. All shades of brown though

Is it possible for 2nd child to have got her colouring from DH alone? Or is it likely that there is someone in my ancestry who is white-Caucasian and those genes have made their way down the ages into my child?

She definitely wasn't switched at birth

yes have you seen the cases of twins where one is white and one black. Its genetics and genes can filter down from relatives.

Hair and eye colour genetics isn't as simple as dark = dominant and fair = recessive.

I won't pretend that I understand more about gene expression than that, though

My children are mixed white/Indian and look completely white, much to my surprise (I figured by blonde haired, blue eyed genes stood no chance!). My son has pale brown hair with golden highlights. I doubt there are any Caucasian genes going back in my husband's family, but you don't actually need fair hair genes from both parents in order to produce a fair haired child.

"you don't actually need fair hair genes from both parents in order to produce a fair haired child"

Really? I thought some of these traits could be dominant but that you'd need to get the gene from both parents...

No, I don't think that's the way it works with hair colour. Like I said, it isn't simply a case of dark hair genes being dominant over fair hair genes.

Hair colour comes from about 15 genes, all producing (or not) certain levels of colour. If the overall total is not much dark hair colour, you're blonde. Overall total of maximum colour molecules - black hair. Some of the 15 molecules have a reddish variant => slight reddish tinge to very red hair.

Similar for skin colour. With eyes, there's various shades of brown which are dominant to a greater or lesser extent over blue colours, but again at least four genes so 8 lots of dye.

Add quirks like some genes for colour failing to be switched on and you can have albinism or just a lighter colour than expected.

I had a neighbour who was black and her husband was white.

Their daughter was to all intents and purposes white: blonde, blue eyes, narrow nose. I had (wrongly) assumed that she was his from a previous relationship or adopted. When I knew them better the mum remarked about being pregnant over millenium NYE with (daughter). I hope I wasn't too visibly surprised.

I now know never ever to make assumptions about anyone's ancestry or race.

Yes but a lot of black people coming from America or the Carribean have mixed heritage from way back so I tend to be less surprised about the children of black people looking fair. The thing that surprised me is given my monolithic Asian background, how did I manage to have a blonde child?

NotCitrus that's very interesting. So much more complex than what we were taught in GCSE biology

At least no one's asked me if I'm the nanny yet!

My dad is very dark, black hair with olive skin. Mother very light skinned and gingery blonde hair. My brother and I are both fair (but less so than DM) and blonde. ExH is auburn-y (although hair darkened to being brown with age) and fair but not pale skin, yet middle DC has brown hair and olive skin. Youngest is white as a ghost with bright ginger hair. DD is more my colouring, white blonde hair and fair skin. Genetics is a fascinating thing!! It's perfectly possible (and indeed you have living proof!) that the gene for blonde hair can be dominant.

I used to work for a family where child 1 was olive skin, dark hair, child 2 was very pale with red hair and I think iirc the third was blonde and blue eyes. Parents were Jewish.

Have you read 'The Midwich Cuckoos' by John Wyndham OP?

No but I see the Village of the Damned is based on the novel, which I have seen. My child does not look like those children!! However it is a slightly odd sensation to give birth to a child that looks nothing like you (features as well as colouring) . We love each other to bits though and of course it doesn't matter, but I do find it very intriguing and it's always coming up because people are so surprised when they see her

You might like this article chipper, about the problems with being a brown parent of a white-looking baby, and the assumptions people make.

www.the-pool.com/life/parenting-honestly/2016/35/up-with-the-kids-robyn-wilder-on-being-mistaken-for-an-au-pair

I'm not sure about hair colour, but am on slightly stronger ground with eye colour - it's to do with the amount of melanin produced. So genetic, yes, but it could simply be that the melanin production in your DC2's case is lower than it should/could be for some undisclosed, possibly genetic, possibly other, reason.
If she's very fair as well, then yes, it would seem that she has a generic reduction in melanin production for some reason (probably some gene that should switch it on, hasn't quite worked properly).
The only worry would be, if this is the case, how low her melanin production is, assuming she's not albino? I would assume that doctor's would have picked that up if she were. Low melanin production could have knock on health effects in respect of skin issues, eye issues and low vitamin D issues - but this is all supposition.

Have you asked your GP at all?

I am a mixed race molecular biologist (not human genetics), but I see you've already got your answers, just wanted to join in!

No she's definitely not albino, her skin is quite a nice tan colour, so there is the merest hint of me in her in that respect I suppose

You might find that her skin darkens as she gets older. My five year old has quite an olive complexion and tans really easily. My not yet two year old is still quite pale, as was his sister at that age.

Friend of mine at school had similar background and went from blonde baby to dark reddish brown hair by mid-teens. Her mum did a chronological collage of photos that was quite something! Otherwise you'd just think she dyed her hair.

I remember feeling 'guilty' that dc1 wasn't noticeably mixed race. She looked exactly like me. My x's family used to remark on it, and not in a ''oh the wonders of genetics way", in a ''hmm this is strange'' way. I felt at the time. DC2 her father's daughter and so consequently strangers in shops ask me if they have the same father.

I know a couple where the mother is Israeli descent and the father Swedish. One child is dark and olive skinned and the other is blonde and blue eyed. I also know another couple where mother is white and father is Indian and one child is pale and ginger and the other dark.

OP, is there any possibility that there is Caucasian blood in there somewhere? I do know that various white rubber planters in colonial Malaya fathered various babies who they never acknowledged, and I don't suppose it was any different elsewhere in Asia. Sometimes those babies were handed over to missionaries and made their way into the Eurasian community, and sometimes they were brought up by their mother (and step-father if she married) or their GPs, as members of their mother's community.

Lumela I think that's very unlikely due to the class and social background of my parents families but I do wonder if maybe somewhere along the line someone married a white/non-Asian woman (more likely than a female member of the family marrying a white man). Or maybe it's from way way back eg Alexander the Great and his many progeny Can a throwback gene throwback that far?

I'm mixed race (Asian/white) and my husband is white. My first child has pale white skin, blue eyes and dark brown hair. People are always suprised that we are related as we look so different. My other child has a golden complexion, brown eyes and brown hair. I think first child's colouring has to come from the grandparents who have pale skin, blue/green eyed. I find it fascinating

I'm not sure if you'd enjoy this book or be totally horrified The Tea Planters Wife

At 18 months she's still as blonde as ever and has gorgeous grey-blue eyes. It's still bewildering but also lots of fun!