Aliens and the Venter/Watson Genomes

All the Venter hubub today reminds me of a scenario that Oliver Morton offered at SciFoo:

Imagine the human race is wiped out. Aliens come down from the sky, and want to see who these humans were. All they'd have to go on would be the DNA of Craig Venter and James Watson. So at best, they could come up with a floc of Venter and Watson clones. Oy.