The phenotypic distribution of quantitative traits in a wild mouse F1 population.

The human complex diseases such as hypertension, precocious puberty, and diabetes have their own diagnostic thresholds, which are usually estimated from the epidemiological data of nature populations. In the mouse models, numerous phenotypic data of complex traits have been accumulated; however, knowledge of the phenotypic distribution of the natural mouse populations remains quite limited. In order to investigate the distribution of quantitative traits of wild mice, 170 F1 progeny aged 8-10 weeks and derived from wild mice collected from eight spots in the suburbs of Shanghai were tested for their values of anatomic, blood chemical, and blood hematological parameters. All the wild mice breeders were of Mus. m. musculus and Mus. m. castaneus maternal origin according to the single nucleotide polymorphism (SNP) markers of the mitochondrial DNA. The results showed that phenotypes in wild mice had a normal distribution with four to six times the standard deviation. For the majority of the traits, the wild outbred mice and laboratory inbred mice have significantly different ranges and mean values, whereas the wild mice did not necessarily show more phenotypic diversity than the inbred ones. Our data also showed that natural populations may have some unique phenotypes related to sugar and protein metabolism, as the mean value of wild mice differ dramatically from the inbred mice in the levels of blood glucose, BUN (blood urea nitrogen), and total blood protein. The epidemiological information of the complex traits in the nature population from our study provided valuable reference for the application of mouse models in those complex disease studies.