By Brandon Keim Wired Science May 1, 2009   http://www.facebook.com/ext/share.php?sid=84359922162&h=0sFhj&u=dk3Jh&ref=mf   Scientists have traced the genetic lineage of the new H1N1 swine flu to a strain that emerged in 1998 in U.S. factory farms, where it spread and mutated at an alarming rate. Experts warned then that a pocket of the virus would someday evolve [...]