DNA and inherited skin tone

[Zaphod99]

A second cousin has taken up with a very nice Singaporean girl who is dark skinned. Not black but not white. The girl's father is white Caucasian and her mother is as far as we know 100-percent Singaporean. The girl is darker skinned than her mother. It is easy to find articles on the internet explaining that if two mid-range skin coloured parents have a child who inherits the darker skin gene from both of them, that he/she can end up with darker skin than his two parents.

However how can it be explained that this girl is darker than her mother, even though she has a Caucasian father. I will also add that she has three or four siblings who are all also darker than the mother.  There is no reason to doubt that the 100% (or close to it) Caucasian father is genuinely the father of all his children.

Zaph

[Mike in Cumbria]

I can't answer your question, but would point out that skin colour is not the result of a single gene, but multiple genes, working in all sorts of non-additive combinations. The answer will lie somewhere in that web of complex relationships between the different genes.

[melba_schmelba]

However how can it be explained that this girl is darker than her mother, even though she has a Caucasian father.

Older generations avoid the sun, younger generations seek it out.

[Erato]

Aside from the genes which control baseline skin color, there are other genes which control the "tanability" of the skin in response to UV radiation.  Some people tan readily and others do not.

[heywood]

The girl's father is white Caucasian and her mother is as far as we know 100-percent Singaporean.
Zaph

 ‘as far as we know’ 
‘100 -percent Singaporean’ 

I know little of Singapore but is there not a long established diverse ancestry?

[trystan]

Indeed from a wonderful chap I knew from Singapore, he informed me that the people there are predominantly of Chinese or Indian descent.

Trystan

[Ruskie]

I agree with those who have suggested that she is likely to spend more time in the sun than her mother. Some Asian cultures see white skin as attractive, use whitening products, avoid the sun and cover their skin even when driving. Any who don’t shield from the sun may find their skin gets more tanned.

[Mike in Cumbria]

The girl's father is white Caucasian and her mother is as far as we know 100-percent Singaporean.
Zaph

 ‘as far as we know’ 
‘100 -percent Singaporean’ 

I know little of Singapore but is there not a long established diverse ancestry?

I don't know much about Singapore either, but apparently yes, it's very ethnically diverse.
So there are lots of factors at play.

[KGarrad]

The girl's father is white Caucasian and her mother is as far as we know 100-percent Singaporean.

That doesn't mean that he hasn't inherited DNA from his father's family, with a possible link to darker skin?

My family tree is 100% English back to 1550; but I tan very easily.