Meeting Abstract
Because Major Histocompatibility Complex (MHC) genes encode the proteins responsible for activating the immune system during infection, genetic variation at the MHC is critical for health and, by extension, survival and reproduction. MHC diversity or possession of a particular MHC allele can purportedly influence an individual’s lifetime reproductive success (LRS) via energetic trade-offs between immunocompetence and reproduction. Although researchers have shown relationships between MHC variation and various proxies of fitness, e.g. health and survival, few have examined if the MHC is related to the ultimate measure of fitness, the production of offspring. Using wild, ring-tailed lemurs (Lemur catta) under long-term study at the Bezà Mahafaly Special Reserve, Madagascar, we evaluated if LRS was correlated with maximal MHC diversity or the possession of specific MHC supertypes. Of 205 infants born to 62 females from 2005-2012, 130 were successfully weaned and 75 died prior to weaning. Although MHC diversity and LRS were uncorrelated, the possession of particular supertypes was correlated with offspring survival to weaning (z value=7.622, p value=0.000***). Other supertypes were associated with failure to give birth (z value=3.797, p value=0.000***) or offspring death before weaning (z value=3.932, p value=0.000***). Thus, an individual’s specific MHC genotype strongly influenced LRS. These relationships disappeared, however, during two severe droughts in 2006 and 2010. As the climate of Madagascar is further altered by human disturbance, the disruption of selective pressure acting on genetic make-up and LRS might increase the threats from population fluctuations and resultant genetic drift. Funded by NSF and Duke University.
