I think so many of us learn elegant things about mendelian genetics in high school that can sort of mislead us if we don’t go on to learn more about life science than that.

Mendel’s pea plants with traits governed by single sets of genes tell an important story, but it’s just the beginning of the story — which I think is maybe something people don’t appreciate.

It’s like with the so-called gay gene that everybody was looking for before we learned how hopelessly naïve that idea is. I mean, human sexuality isn’t a purple blossom. Sexual behavior is governed by many different sets of genes, which can interact with prenatal and postnatal environments in unpredictable ways.

Fingerprints are a great way of illustrating how environmental factors can influence even relatively simple genetic traits.

So, I guess, are identical twins who grow to be slightly different heights.