by Corvi Zeman

It’s possible, but unlikely for the skin colors of twins to be very different.

Identical twins have to have the same skin color, because they have the exact same genes, they started out as one embryo that split into two. Fraternal twins start as two seperate embryos, and are as similar as any other siblings.

So suppose a black man and a white woman have a daughter. The child has two copies of each gene for skin color, one from her father, and one from her mother. From her father, she gets all of genes for black skin. From her mother, she gets all genes for white skin. So her skin color comes out somewhere in the middle – on every single gene, she has one black version from her dad and one white version from her mom.

Now let’s suppose the mixed-race daughter finds another mixed-race man to marry, and they decide to have a kid together. Their kid gets half her skin color genes from her mom, and half her skin color genes from her dad. But this time, she could get a black or a white gene from her mom, cause her mom has one of each. Same for her dad.

For every single skin color gene, she has a 50% change of getting a white one from mom, and a 50% chance of getting a black one from mom. She has a 50% chance of getting black or white from dad, too.

So their daughter has:

  • 25% chance of getting the black gene from BOTH parents
  • 50% chance of getting one black gene and one white gene
  • 25% chance of getting the white gene from BOTH parents

There are a whole bunch of genes that affect skin color. So most of the time, the kids will get the 50% chance and they’ll look somewhere between white and black, like their parents.

But maybe one of the kids gets that 25% chance of getting the black gene from both parents a whole bunch of times. If there are ten skin color genes (I don’t know how many there are), you have a one in a million chance of getting the all-black on all ten of them.

If you have two kids, and they’re twins, maybe one of them has the one-in-a-million chance of getting all the black genes, and one of them has the one-in-a-million chance of getting all the white genes.

It could happen.

And it has.

Kian and Remee are nine year old twins. Their mixed-race parents both have a black father and a white mother. You can read more about them in this article.

Source: Quora

 

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