TY - JOUR
T1 - Cryptic female choice favours sperm from major histocompatibility complex-dissimilar males
AU - Løvlie, Hanne
AU - Gillingham, Mark A. F.
AU - Worley, Kirsty
AU - Pizzari, Tommaso
AU - Richardson, David S.
N1 - H.L. was supported by a PhD studentship from the Department of Zoology of Stockholm University, by the Schwartz Foundation, Lars Hierta’s Foundation, Knut & Alice Wallenberg’s Foundation, the Royal Swedish Academy of Science and the Royal Swedish Academy of Agriculture and Forestry. M.A.F.G. was funded by a scholarship from the Biotechnology and Biological Science Research Council. K.W., T.P. and D.S.R. were supported by a research grant from the Natural Environment Research Council (NE/D002788/1). T.P. was also supported by a fellowship from the Swedish Research Council for Environment, Agriculture and Spatial Planning.
Electronic supplementary material is available at http://dx.doi.org/10.1098/rspb.2013.1296 or via http://rspb.royalsocietypublishing.org.
PY - 2013/10
Y1 - 2013/10
N2 - Cryptic female choice may enable polyandrous females to avoid inbreeding or bias offspring variability at key loci after mating. However, the role of these genetic benefits in cryptic female choice remains poorly understood. Female red junglefowl, Gallus gallus, bias sperm use in favour of unrelated males. Here, we experimentally investigate whether this bias is driven by relatedness per se, or by similarity at the major histocompatibility complex (MHC), genes central to vertebrate acquired immunity, where polymorphism is critical to an individual's ability to combat pathogens. Through experimentally controlled natural matings, we confirm that selection against related males' sperm occurs within the female reproductive tract but demonstrate that this is more accurately predicted by MHC similarity: controlling for relatedness per se, more sperm reached the eggs when partners were MHC-dissimilar. Importantly, this effect appeared largely owing to similarity at a single MHC locus (class I minor). Further, the effect of MHC similarity was lost following artificial insemination, suggesting that male phenotypic cues might be required for females to select sperm differentially. These results indicate that postmating mechanisms that reduce inbreeding may do so as a consequence of more specific strategies of cryptic female choice promoting MHC diversity in offspring.
AB - Cryptic female choice may enable polyandrous females to avoid inbreeding or bias offspring variability at key loci after mating. However, the role of these genetic benefits in cryptic female choice remains poorly understood. Female red junglefowl, Gallus gallus, bias sperm use in favour of unrelated males. Here, we experimentally investigate whether this bias is driven by relatedness per se, or by similarity at the major histocompatibility complex (MHC), genes central to vertebrate acquired immunity, where polymorphism is critical to an individual's ability to combat pathogens. Through experimentally controlled natural matings, we confirm that selection against related males' sperm occurs within the female reproductive tract but demonstrate that this is more accurately predicted by MHC similarity: controlling for relatedness per se, more sperm reached the eggs when partners were MHC-dissimilar. Importantly, this effect appeared largely owing to similarity at a single MHC locus (class I minor). Further, the effect of MHC similarity was lost following artificial insemination, suggesting that male phenotypic cues might be required for females to select sperm differentially. These results indicate that postmating mechanisms that reduce inbreeding may do so as a consequence of more specific strategies of cryptic female choice promoting MHC diversity in offspring.
KW - genetic relatedness
KW - major histocompatibility complex
KW - postcopulatory sexual selection
KW - sperm choice
U2 - 10.1098/rspb.2013.1296
DO - 10.1098/rspb.2013.1296
M3 - Article
SN - 0962-8452
VL - 280
JO - Proceedings of the Royal Society B: Biological Sciences
JF - Proceedings of the Royal Society B: Biological Sciences
IS - 1769
M1 - 20131296
ER -