In the mid-nineteenth century, Gregor Mendel, a friar who taught natural science in the provincial Austro-Hungarian capital of Brunn (today Brno, Czech Republic), began to experiment with breeding garden peas. Meticulously recording his observations of their inherited traits over a number of generations, he developed the basis of the modern science of genetics. Mendel's discoveries were so far in advance of their day that it wasn't until 50 years...