As the article is pretty old I suggest looking at a more recent discussion of the topic: http://www.nature.com/nature/journal/v531/n7592_supp/full/531S10a.html

As the article is pretty old I suggest looking at a more recent discussion of the topic: http://www.nature.com/nature/journal/v531/n7592_supp/full/531S10a.html http://www.nature.com/nature/journal/v531/n7592_supp/full/53...