A New Twist on Behavioral Genetics by Incorporating Wild-Derived Mouse Strains

Abstract

Abstract:Behavior has been proven to be extremely variable among human individuals. One of the most important factors for such variations of behavior is genetic diversity. A variety of mouse strains are reportedly suitable animal models for investigating the genetic basis of large individual differences in behavior. Laboratory strains have been shown to exhibit different behavioral traits due to variations in their genetic background. However, they show low-level genetic polymorphism because the original colony used for establishing the strains comprises a relatively small number of mice. Furthermore, because the laboratory strains were derived from fancy mice, they have lost the original behavioral phenotype of wild mice. Therefore, incorporation of inbred strains derived from wild mice of different mouse subspecies for behavioral studies is a marked advantage. In the long-term process of establishing a variety of wild-derived inbred strains from wild mice captured all over the world, a number of strains have been established. We previously identified a marked variety in behavioral traits using a Mishima battery. This review reports on the usefulness of wild-derived strains for genetic analyses of behavioral phenotypes in mice.

26. Equilibrium vitrification of mouse embryos

“…Ancestors of the MSM strain were introduced directly into the laboratory from the wild [4], while the JF1 strain has a long history as a Japanese fancy mouse breed since the 1700s [3]. The ratios of polymorphic markers that are different from common inbred strains are consistently higher in MSM mice than in JF1 mice [26].…”

“…The ratios of polymorphic markers that are different from common inbred strains are consistently higher in MSM mice than in JF1 mice [26]. In a recent review, therefore, the JF1 strain was classified as a fancier-derived strain and not a wild-derived strain, although it is genetically considered to belong to the M musculus molossinus subspecies [3]. The genetic relationship between the JF1 strain and common laboratory strains is currently under investigation (Dr. T. Shiroishi, personal communication).…”

“…The MSM strain might be more suitable for positional cloning and quantitative trait locus analysis than the JF1 strain, because these analyses need as many polymorphic markers as possible for generating high-density linkage maps. These mice have been used extensively for behavioral analysis [3,4,27]. Germline-competent embryonic stem cell lines from the MSM strain are also available [28].…”

“…For example, in the case of genetic mapping, there are often substantial ''blind spots'' in genomes caused by the lack of genetic variation among the inbred strains involved in analysis. To circumvent this shortcoming associated with the existing strains of laboratory mice, wildderived mice from different origins have been introduced into research laboratories, many of them established as inbred strains [3]. These strains can be used successfully as unique resources to discover new allelic variations and modifiers of spontaneous, randomly introduced or genetically engineered mutations [2].…”

Genomic Mixing to Elucidate the Genetic System of Complex Traits

“…The phenotypic diversity is believed to be a result of genetic diversity among wild-derived strains, as shown by several studies on genomic polymorphisms of these strains [17,18,20,23,27]. As each wild-derived strain has a different evolutionary history, we can expect a unique haplotype in each strain [16]. Therefore, mixing eight wild-derived strains to produce an HS is markedly useful to expand genetic diversity in the colony.…”