Jenna Bush a hit in Europe

The Washington Times ^ | 7 July 2005 | Stephanie Mansfield

[exnavychick]

I'm trying to figure out the girls' genetic makeup. Neither mom or dad are redheads...

Neither were my parents, and yet...here I am. :) Just a throwback to my great-grandfather I've been told. A couple of recessives is all it takes. :)

[BobS]

Red hair and blue eyes are more recessive genes than blond genes. I know there are variations. I was using the example of parents that have genes for purely dark eyes and hair and have purely recessive genes for red hair and blue eyes. To simplify the the discussion. You get AA(25%), AB + BA(50%), and BB (25%). John Thune and his wife had 4 to 1 odds against them with their 1st red-haired girl. And I believe 4^2 to 1 odds against them having a second red-haired girl. Am I wrong with the math? Is it 8 to 1 odds for the second child?

[AnAmericanMother]

Here ya go - I found this very helpful:

Had to get an Aussie professor at a local university to explain to me who "Nifty's Boyos" were though . . .

[Politicalities]

To simplify the the discussion...

That's the problem. You're oversimplifying. The human genome isn't that simple, and in this case your simplification omits important details.

You're correct in saying that the odds of two parent organisms, each carriers of a recessive gene, giving birth to two offspring that both have the recessive reinforced is 1/4². But that's not 1/8, it's 1/16 :)

But again, human genetics isn't that simple. Another way of looking at it, though still oversimplified, is this: there are two gene locations, one of which specifies either fair hair (F) or dark hair (D), and the other of which specifies either red hair (R) or non-red hair (N). Fair hair is recessive while red hair is dominant. A child who has genes for both fair and red hair will be a redhead.

Suppose John Thune is FD RR, while Kimberley Thune is FF NN. Their chances of having a single redheaded offspring are 50%, and two redheaded offspring are 25%. This, again, is an oversimplification of the actual genome, but is closer to reality than the 6.7% you came up with.

[BobS]

But again, human genetics isn't that simple...

I know it isn't that simple. I am trying to remember genetics as it was taught to me in high school 35 years ago in biology class; it's not my professional field now. I do have a basic understanding of this before they put rubbers on cucumbers recently, do you agree?

We have the correct math together. Shall we say that each child has the same chances at these genes as the one before it? I am looking at probability mathematically as you are looking at it biologically. We agree on the solution and disagree on the approach. Because we are in different fields of expertise.

Let's talk some more about this tomorrow or so because I must sleep. And I want to sleep as late as I am humanly able to tomorrow.

[Gum Shoe]

What's with the ring I see on the left hand there? Is this the ring the First Lady was busily denying meant anything?

[beyond the sea]

Barbara is beautiful.

[beyond the sea]

Jenna is sexy and has the right curves, but Barbara is elegant and will surpass her sister in sexiness within a few years.

Very, very true.

[beyond the sea]

She was cute..... looked like Opie.

[beyond the sea]

Ditto

[beyond the sea]

Quite possibly. Barbara may have a wild side. And her ladylike demeanor is what makes it an exciting thought.

She sure is elegant and demure.