In the article “Pathological Aggression in “Fierce” Mice Corrected by Human Nuclear Receptor 2E1,” by Brett S. Abrahams, Melvin C. H. Kwok, Eric Trinh, Saeed Budaghzadeh, Sazzad M. Hossain, and Elizabeth M. Simpson, which appeared on pages 6263-6270 of the July 6, 2005 issue, a portion of the legend to Figure 2 was modified incorrectly by the printer. In that legend, the sixth sentence should read as follows: “The arrowhead indicates the Ec, which is thin in fierce relative to Wt.”