Black and white twins

I smell a sitcom:

Remee, who weighed 5lb 15oz, was blonde and fair skinned. Her sister Kian, born a minute later weighing 6lb, was black.

Both Kylie and her partner Remi Horder, 17, are of mixed race. Their mothers are both white and their fathers are black. According to the Multiple Births Foundation, baby Kian must have inherited the black genes from both sides of the family, whilst Remee inherited the white ones. [...]

Skin colour is believed to be determined by up to seven different genes working together.

If a woman is of mixed race, her eggs will usually contain a mixture of genes coding for both black and white skin. Similarly, a man of mixed race will have a variety of different genes in his sperm. When these eggs and sperm come together, they will create a baby of mixed race.

But, very occasionally, the egg or sperm might contain genes coding for one skin colour. If both the egg and sperm contain all white genes, the baby will be white. And if both contain just the versions necessary for black skin, the baby will be black.

For a mixed-race couple, the odds of either of these scenarios is around 100 to one. But both scenarios can occur at the same time if the woman conceives non-identical twins, another 100 to one chance.

This involves two eggs being fertilised by two sperm at the same time, which also has odds of around 100 to one.

If a sperm containing all-white genes fuses with a similar egg and a sperm coding for purely black skin fuses with a similar egg, two babies of dramatically different colours will be born.

The odds of this happening are 100 x 100 x 100 - a million to one.


40 Responses:

  1. dsgood says:

    Note that Remee might not be blonde all her life. I was blond in childhood, though by about age 12 I was "dirty blond." My hair continued darkening till it became black.

  2. chaosmeika says:

    hmm, for a second I thought it was that show on FX, but this was a much better scenario. Thanks for the news.

  3. bassfingers says:

    I smell a sitcom

    The only question becomes, which Olsen twin do you strap to the tanning bed?

  4. hollyqueen says:

    The fact that they say one is white and one is black is so annoying. One is certainly paler than the other, but neither of them is just one thing, damnit!

    • pauraque says:

      It's an interesting story, but that bothered me too. They're implying that "black" and "white" are discrete biological categories, when in fact they are subjective cultural categories.

      • spudtater says:

        Black and white were originally just descriptions of skin colour. Frankly, I think they should remain as such.

        • 33mhz says:

          Nevertheless, though those terms are describing physical characteristics that do exist, what combinations of physical characteristics get parsed into what racial categories by an observer is largely culturally determined, as with the apartheid-era "pencil test" in South Africa.

    • wyndebreaker says:

      I agree. If a person were really half white and half black, they would be gray.

    • unwoman says:

      It's a British thing. It's completely different than the way Americans talk about race. I can't even try to understand it.

      • spudtater says:

        What's complicated about it?

        White = pale skin; tends to burn in the sun, but good at generating vitamin D; more frequently accompanied by fairer hair and eye colours.

        Black = dark skin; tends not to burn, but not so good at vitamin D production; almost always accompanied by black hair and brown eyes.

        • hollyqueen says:

          Most of the people I know who think of themselves as black have brown hair. And some have hazel or green eyes. Fewer of those, however.

          • spudtater says:

            > some have [...] green eyes

            Which, to me, suggests that they are not entirely black.1

            There does seem to be a difference between how Brits and USians perceive race. To me, "being black" or not is not something your mindset can alter. Somebody of mixed race doesn't get the choice of being black or being white; they're just somewhere in-between, depending on their genes.

            I don't know how that strikes you, but I think it's a healthier attitude. In an ideal world, culture shouldn't be split along genetic boundaries; can you imagine if somebody with chestnut hair was pressured to "make up her mind if she was redhead or brunette"?

            Does that make sense?   8^S

            [1] N.B. I don't know the frequency of green eyes in people of pure african anscestry... as I understand it it is vanishingly small. I could be wrong, though.

  5. catenoid says:

    There are so many million-to-one chances out there, you're bound to run into a few sooner or later.

  6. insomnius says:

    Just goes to show: black people are fatter than white people.

  7. baconmonkey says:

    daddy is only 17.
    and holy crap, with the font the article uses, the 'i' in in Kian looks an awful lot like an 'l', and in skimming, I kept doing re-reads, cuz I kept seeing "baby Klan"

  8. mcfnord says:

    totally cute.

  9. spudtater says:

    Damn you! Stop defying entropy! It's not allowed!   8^)

  10. djproctology says:

    Her sister Kian, born a minute later weighing 6lb, was black.

    At first I read "Kian" as "Klan" and that gave it a whole new dimension of funny.

  11. bebopmonkey says:

    i'm sorry, but i read "baby Kian" as "babt KLAN" the first time and freaked out.

  12. rakafkaven says:

    Not to be all "I took high school biology ten years ago", but the following:

    But both scenarios can occur at the same time if the woman conceives non-identical twins, another 100 to one chance.

    This involves two eggs being fertilised by two sperm at the same time, which also has odds of around 100 to one.

    ... seems to indicate that someone did not. They mention that non-identical twins are a 100-to-one chance, and then go on to describe in detail how non-identical twins are conceived... but mention the odds again as something additional. It's like saying: "The coin came up heads, which has a one in two chance. This involves the coin landing on the side which is not tails, which also happens one time in two."

    The final calculated odds omit this redundancy, which just reinforces my impression that the article's author had a very loose understanding of the information they received.

    • pozorvlak says:

      I think it's P(fraternal twins) * P(completely white baby) * P(completely black baby) = 1/100 * 1/100 * 1/100 = 1/106. But it is poorly-written, I agree.

      • wfaulk says:

        That assumes that the darker-skinned baby is "completely black", which, unless they've started using the Jheri Curl on her already, seems to be demonstrably untrue.

      • igorlord says:

        They postulate that:

        • P(fraternal twins) = 1/100
        • P(completely white or black baby) = 1/100
        • Now, if we know the color of one baby and consider either white of black baby to be equally probable, then:
          P(completely white or black baby of the opposite color) = P(completely white or black baby) / 2

        Therefore, the probability of the given situation is actually:
        P(fraternal twins) * P(completely white or black baby) * P(completely white or black baby of the opposite color) = 1/100 * 1/100 * 1/200.

        The article is wrong by the factor of 2!

        • pozorvlak says:

          Good point, but it's actually P(white baby) = P(black baby) =~ 1/100, so P(monoracial baby) would be 1/50. So the probability will actually be P(fraternal twins) * P(first baby is monoracial) + P(second baby is monoracial of opposite colour) = 0.01*(0.0002) = 2/106.

          But anyway, I think the assertion that P(completely white baby) = 1/100 is only to within order-of-magnitude (if that: seven genes which must be of a certain allele in sperm and egg should give a probability of 2-14 =~ 1/16,000, as far as I can see). And as jwz says below, math is hard, and probability is hard even by the standards of math, and this is from the Daily Mail, which probably thinks Science is a conspiracy by illegal immigrants to deny hard-working Blitz veterans their cups of tea.

          • igorlord says:

            I guess it depends on how you interprent: "the odds of either of these scenarios is around 100 to one."

            In any case, 1/100 and 1/16,000 are NOT within a order of magnitude! But 1/16,000 is derived from the assumption that each gene can be selected completely independently from other genes, which is not necessarily the case. But this is a gene biology question, which I do not know much about.

            The math, however, is as simple as it gets. Still, you are probably right that even this math is way over the head of Daily Mail science and math standards.

    • jwz says:

      Yeah, I noticed that. This reporter was clearly from the "stenography" school of reporting. Math is hard, let's go shopping.

  13. whittles says:

    I'm curious what they'll look like in 10 years. so many people I know (esp mixed folks) lightened and or darkened through aging. You can't tell toddler pictures of my sister and I apart, but now everyone assumes I'm white and she's hispanic.

  14. sherbooke says:

    Would a US TV Network actually base a sitcom on miscegenation? Umm, from what I've seen of US TV I'd say no, although the UK buyers could be applying filters. Firefly has a black and white couple. Umm. I'm sure there're a few more.

  15. irma_vep says:

    What a cool looking family.