Parents & Babies & Skin Color

“Law and Order” had a re-run with skin color theme that fogged over my biology 101 and since someone started eye color, I thought I’d toss this in, too.

The “Law and Order” story line had a “black” father who had passed for white all his adult life. He married a blond blond woman and their child was a rather dark-skinned “black” child.

Now, just forget the story.

I thought skin color had to do with quantative genes* and what ever your body had for color (absent a tan) was what you carried for genes.

So according to “Jois’ Theory” a pair of parents could not have children darker skinned than either one of them…

So did I take a left someplace here? BTW: I forget exactly what *quantative genes are…

Thank you in advance, I’m going to watch from behind this lead partition.

Jois’ Theory doesn’t hold water its got so many holes. I’m no geneticist but from my understanding, not only is the above example possible, but its also possible that two light skinned people who had always considered themselves ‘white’ could have a dark skinned baby if one of them had a long lost ancestor who had the genetic trait of dark skin.

From my understanding, the gene for light skin is a recessive one and the gene for dark skin is a dominant one. This is grossly oversimplified I’m sure, but I just know someone will come in and clarify upon what I’ve said…{drum roll}

I don’t know which (light or dark skin) is dominant, but if dark skin is dominant, as voltaire guessed, than the Jois theory is correct.

Assuming dark skin dominant, l = light skin gene (recessive) and D = dark skin gene (dominant).

For the 2 parents to both be light-skinned, they would both have to have ll (2 light skin genes) and would only be able to pass on an l gene to their children, making them all light-skinned.

If one parent has Dl, that parent would be dark-skinned, because the D gene is dominant, and any child who got a D gene from that parent would also be dark skinned.

If one parent has DD, that parent would be dark-skinned and all children would get a D from that parent and be dark-skinned also.

If both parents are Dl, they would both be dark-skinned and any child who got a D from one or both parents would be dark-skinned.

If one parent is Dl and one is DD, all children would be either Dl or DD and all parents and all children would be dark-skinned.

If both parents are DD, all children will be DD and the parents and children will be dark-skinned.

This is all assuming that skin color is determined by a single gene, which is not necessarily so.

None of this is correct if light skin is dominant.

Thus concludes the simplistic genetics lesson for today.

Your Official Cat Goddess since 10/20/99.

“I get along well with everybody.” --I.M.F.

Why is it that you can never find a policeman, doctor or <font color=green>biologist </font> when you need one?

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