As orgies go, it's pretty wild. Hundreds of whip-wielding participants pile into a seething ball. Stripping naked, they entwine and embrace, striving to make an intimate connection and consummate the union. If beaten to it by a rival, they move on to another partner until they get lucky. And chances are, it's all carrying on right now in your garden.

But don't call the police or reach for your camcorder yet. These swinging debauchers aren't human, they're single-celled algae called Chlamydomonas, commonly found in soil and water. Affectionately nicknamed'chlamy'by the scientists who study them, these slimy green organisms and their rumbustious sex lives have a surprising connection with us and how our bodies work. Dissecting that connection is leading researchers to uncover a story that starts more than half-a-billion years ago and ends in modern-day illnesses such as diabetes, cancer and obesity. Along the way it touches the origin of bodies, beauty and symmetry, even helping reveal what makes individuals unique.