The Punnett Square
If I have children, there's a one-in-two chance that I will pass on the defective gene to them.
That doesn't mean they'll look like August, but they'll carry the gene that got doubledosed in August and helped make him the way he is.
If I marry someone who has the same defective gene, there's a one-in-two chance that our kids will carry the gene and look totally normal,
a one-in-four chance that our kids will not carry the gene at all, and a one-in-four chance that our kids will look like August.
If August has children with someone who doesn't have a trace of the gene, there's a 100 percent probability that their kids will inherit the gene,
but a zero percent chance that their kids will have a double dose of it, like August.
Which means they'll carry the gene no matter what, but they could look totally normal.
If he marries someone who has the gene, their kids will have the same odds as my kids.
This only explains the part of August that's explainable. There's that other part of his genetic makeup that's not inherited but just incredibly bad luck.
Countless doctors have drawn little tic-tac-toe grids for my parents over the years to try to explain the genetic lottery to them.
Geneticists use these Punnett squares to determine inheritance, recessive and dominant genes, probabilities and chance.
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