Submitted to: Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2013
Publication Date: 9/24/2013
Publication URL: http://handle.nal.usda.gov/10113/58813
Citation: Morris, C.F., Fuerst, E.P., Beecher, B.S., Mclean, D.J., James, C.P., Geng, H. 2013. Did the house mouse (Mus musculus L.) shape the evolutionary trajectory of wheat (Triticum aestivum L.)?. Ecology and Evolution. 3:3447-3454. Interpretive Summary: Wheat is one of the most successful domesticated plant species in the world. The relationships among humans, wheat and the house mouse present an intriguing scenario for selection and evolution. Bread wheat (T. aestivum) cannot persist in the wild without the aide of humans, as its tough rachis and free-threshing glumes prevent competitive seed dispersal. The present study was aimed at testing the following hypothesis: can the house mouse exert a level of phenotypic selection for kernel texture in wheat such that allele frequency at the Hardness locus is significantly impacted. Did the house mouse shape the evolutionary trajectory of wheat by facilitating the persistence and expansion of hard-texture mutations–a case of soft kernel predation vs. hard kernel avoidance? The results indicate that indeed the house mouse can exert dramatic selection pressure on wheat kernel texture, and support the possibility that hardness mutations persisted as “predation defense” genes in pre-historic agriculture. Here, we demonstrated that the house mouse (Mus musculus) exerts a pronounced feeding preference for soft over hard kernels and the study clearly demonstrates that the house mouse could have played a role in the evolution of wheat, and therefore humankind.
Technical Abstract: Wheat (Triticum aestivum L.) is one of the most successful domesticated plant species in the world. The majority of wheat carries mutations in the Puroindoline genes that result in a hard kernel phenotype. An explanation as to the selection of these hard-kernel mutations has not been established. Here, we demonstrate that the house mouse (Mus musculus) exerts a pronounced feeding preference for soft over hard kernels. At beginning allele frequencies ranging from 0.5 to 0.009, mouse predation shifted the hard allele frequency as much as 10 fold. Studies involving a single hard kernel mixed with ca. 1000 soft kernels failed to recover the mutant kernel. Nevertheless, the study clearly demonstrates that the house mouse could have played a role in the evolution of wheat, and therefore humankind.