Data from: Major histocompatibility complex-linked social signalling affects female fertility

Genes of the major histocompatibility complex (MHC) have been shown to
influence social signalling and mate preferences in many species,
including humans. First observations suggest that MHC signalling may also
affect female fertility. To test this hypothesis, we exposed 191 female
horses (Equus caballus) to either a MHC-similar or a MHC-dissimilar
stimulus male around the time of ovulation and conception. A
within-subject experimental design controlled for non-MHC linked male
characteristics, and instrumental insemination with semen of other males
(N=106) controlled for potential confounding effects of semen or embryo
characteristics. We found that females were more likely to become pregnant
if exposed to a MHC-dissimilar than to a MHC-similar male, while overall
genetic distance to the stimulus males (based on microsatellite markers on
20 chromosomes) had no effect. Our results demonstrate that early
pregnancy failures can be due to maternal life-history decisions (cryptic
female choice) influenced by MHC-linked social signalling.