yes it is a type o ,it was in 2003 <A HREF="http://www.nature.com/cgi-taf/DynaPage.taf?file=/gt/journal/v10/n20/abs/3302068a.html" target="_blank">http://www.nature.com/cgi-taf/DynaPage.taf?file=/gt/journal/v10/n20/abs/3302068a.html</A>