Molecular heterogeneity in major urinary proteins of Mus musculus subspecies: potential candidates involved in speciation.
When hybridisation carries a cost, natural selection is predicted to favour evolution of traits that allow assortative mating (reinforcement). Incipient speciation between the two European house mouse subspecies, Mus musculus domesticus and M.m.musculus, sharing a hybrid zone, provides an opportunity to understand evolution of assortative mating at a molecular level. Mouse urine odours allow subspecific mate discrimination, with assortative preferences evident in the hybrid zone but not in allopatry. Here we assess the potential of MUPs (major urinary proteins) as candidates for signal divergence by comparing MUP expression in urine samples from the Danish hybrid zone border (contact) and from allopatric populations. Mass spectrometric characterisation identified novel MUPs in both subspecies involving mostly new combinations of amino acid changes previously observed in M.m.domesticus. The subspecies expressed distinct MUP signatures, with most MUPs expressed by only one subspecies. Expression of at least eight MUPs showed significant subspecies divergence both in allopatry and contact zone. Another seven MUPs showed divergence in expression between the subspecies only in the contact zone, consistent with divergence by reinforcement. These proteins are candidates for the semiochemical barrier to hybridisation, providing an opportunity to characterise the nature and evolution of a putative species recognition signal.
Mammalian Behaviour and Evolution Group, Institute of Integrative Biology, University of Liverpool, Leahurst Campus, Neston, CH64 7TE, UK.
Jane L
JL
Hurst
Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
Robert J
RJ
Beynon
Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
Stuart D
SD
Armstrong
Mammalian Behaviour and Evolution Group, Institute of Integrative Biology, University of Liverpool, Leahurst Campus, Neston, CH64 7TE, UK.
Amanda J
AJ
Davidson
Mammalian Behaviour and Evolution Group, Institute of Integrative Biology, University of Liverpool, Leahurst Campus, Neston, CH64 7TE, UK.
Sarah A
SA
Roberts
Centre for Proteome Research, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
Guadalupe
G
Gómez-Baena
Institut des Sciences de l'Evolution de Montpellier UMR5554 (UM, CNRS, IRD, EPHE), Université de Montpellier, CC 065, 34095 Montpellier Cedex 05, France.
Carole M
CM
Smadja
Institut des Sciences de l'Evolution de Montpellier UMR5554 (UM, CNRS, IRD, EPHE), Université de Montpellier, CC 065, 34095 Montpellier Cedex 05, France.
Guila
G
Ganem
D000818:Animals; D005060:Europe; D019143:Evolution, Molecular; D005260:Female; D018740:Genetic Heterogeneity; D014644:Genetic Variation; D005843:Geography; D008297:Male; D051379:Mice; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D020543:Proteome; D040901:Proteomics / Q000379:methods; D012641:Selection, Genetic; D013045:Species Specificity
D011506:Proteins; D020543:Proteome; C035737:major urinary proteins