One of my major research projects as an undergraduate involved looking at how major histocompatibility complex (MHC) alleles influence female mate choice preferences, and I worked in conjunction with two of my professors at Ohio Wesleyan University. Females may have mate preferences for male traits that benefit their offspring. We were interested in whether female Poecilia latipinna choose males based on traits that allow them to reduce inbreeding, or increase immune function. One such trait may be the important immune protein, MHC. It has been hypothesized that the more different a male is from the female at his MHC gene, the more attractive he will be. Given this hypothesis, we designed an experiment to test the prediction that females will prefer males with dissimilar MHC genotypes, using a variety of genotyping techniques and the building and implementation of a female choice flow tank.