Today, or what's left of it, is Gregor Mendel's 189th birthday, and as he is one of my heroes, I feel the need to shout about it. Mendel was one of those people who led a modest life, saw and observed the same world as the rest of us, but did it so much better, more insightfully, more thoughtfully, and came up with an idea that is so simple, profound and right that the rest of us will spend the rest of time thinking: how come no one had thought of that before? In his case, it was a few rows of peas (round, wrinkled, etc) sown annually and the produce patiently counted and re-sown, plus maths, that revealed the solution to the bit Charles Darwin hadn't solved: how, from generation to generation, did heredity happen? The nuts and bolts of it? Nowadays we witter on about genes, DNA and all the rest of it, as though these ideas had always been there, but in Mendel's time hardly anyone had so much as a clue, and then Mendel wrote a clue. Some say he tweaked the maths, but e...