Hi Justin,
I'm just going to list the citations as I copied them into my computer. Sorry I don't have the time to clean 'em up. Hopefully you'll get a chance to dig a few up at the library before your paper is due.
Overall conclusion - there's no "gene for aggression". There is a genetic underpinning, as with most behaviors, but the expression appears highly variable depending on environment, species, development, and even litter size. I copied the articles that I thought would be appropriate or have some bearing on your topic.
"Parent-offspring conflict and the genetics of offspring solicitation and parental response", ANIMAL BEHAVIOUR, 2001, 62, 395—407
MATHIAS KOLLIKER & HEINZ RICHNER
"Low central nervous system serotonergic activity is traitlike and correlates with impulsive behavior. A nonhuman primate model investigating genetic and environmental influences on neurotransmission" J. D. Higley and M. Linnoila 1997 Annals of the New York Academy of Sciences, Vol 836, Issue 1 39-56
"The Other "Closest Living Relative": How Bonobos (Pan paniscus) Challenge Traditional Assumptions about Females, Dominance, Intra- and Intersexual Interactions, and Hominid Evolution" Annals of the New York Academy of Sciences 907:97-113 (2000) AMY R. PARISH, FRANS B. M. DE WAAL and DAVID HAIG
Klaus Hacklnder and Walter Arnold "Male-caused failure of female reproduction and its adaptive value in alpine marmots (Marmota marmota)" Behav. Ecol., Sep 1999; 10: 592 - 597
EJ Yang and W Wilczynski, "Relationships between hormones and aggressive behavior in green anole lizards: an analysis using structural equation modeling." Horm Behav, September 1, 2002; 42(2): 192-205
"Progesterone receptors mediate male aggression toward infants"
Johanna S. Schneider, Marielle K. Stone, Katherine E. Wynne-Edwards, Teresa H. Horton*, John Lydon , Bert O'Malley , and Jon E. Levine, PNAS 2003 100:2951-2956
You might want to see if your library has a subscription to the journal
Behavioral Ecology - it usually has a lot of articles on aggression, kin selection, etc.