Hey all. I'm looking for a book I once read, probably about 14-15 years ago. It was about eight people from various times throughout history who for some reason or another turned out to be immortal. Four men and four women, as I recall. After thousands of years, mankind has found the genetic code for immortality, as well as ways to change other things - I can remember one instance where one person had changed their DNA to grow teeth made out diamonds. Any ideas? I'm sorry I don't have any idea who the author was, or any clue as to the title. I've been google searching key words all morning and coming up with zip.