Herding Hemingway's Cats

The language of genes has become common parlance. We know they make your eyes blue, your hair curly or your nose straight. The media tells us that our genes control the risk of cancer, heart disease, alcoholism or Alzheimer''s. The cost of DNA sequencing has plummeted from billions of pounds to a few hundred, and gene-based advances in medicine hold huge promise.

So we''ve all heard of genes, but h...