Genetic differentiation of subspecies of the house mouse Mus musculus and their taxonomic relationships inferred from RAPD-PCR data

Genetic differentiation of six subspecies of the house mouse Mus musculus (Mus musculus musculus. M. m. domesticus, M. m. castaneus, M. m. gansuensis, M. m. wagneri, and M. m. ssp. (bactrianus?) was examined using RAPD-PCR analysis. In all, 373 loci of total length of about 530 kb were identified. Taxon-specific molecular markers were detected and the levels of genetic differences among the subspecies were estimated. Different degree of subspecific genetic differentiation was shown. The most similar subspecies pairs were M. m. castaneus--M. m. domesticus and M. m. musculus--M. m. gansuensis. In our phylogenetic reconstruction, M. m. wagnery proved to be most different from all the other subspecies. Genetic distances between it and other subspecies were two- to threefold higher than those between the "good"' species of the subgenus Mus (e.g., between M. m. musculus and M. spicilegus, M. musculus and M. abbottii). The estimates of genetic similarity and the taxonomic relationships between six house mouse subspecies inferred from RAPD partially conformed to the results based on cytogenetic and allozyme data. However, they were considerably different from phylogenetic reconstructions based on sequencing of the control mtDNA region, which reflects mutual inconsistency of different systems of inheritance.     

Genetic differentiation of subspecies of the house mouse Mus musculus and their taxonomic relationships inferred from RAPD-PCR data

Genetic differentiation of six subspecies of the house mouse Mus musculus (Mus musculus musculus, M. m. domesticus, M. m. castaneus, M. m. gansuensis, M. m. wagneri, and M. m. ssp. (bactrianus?) was examined using RAPD-PCR analysis. In all, 373 loci of total length of about 530 kb were identified. Taxonspecific molecular markers were detected and the levels of genetic differences among the subspecies were estimated. Different degree of subspecific genetic differentiation was shown. The most similar subspecies pairs were M. m. castaneus-M. m. domesticus and M. m. musculus-M. m. gansuensis. In our phylogenetic reconstruction, M. m. wagneri proved to be most different from all the other subspecies. Genetic distances between it and other subspecies were two-to threefold higher than those between the “good”species of the subgenus Mus (e.g., between M. m. musculus and M. spicilegus, M. musculus and M. abbotti). The estimates of genetic similarity and the phylogenetic relationships between six house mouse subspecies inferred from RAPD partially conformed to the results based on cytogenetic and allozyme data. However, they were considerably different from phylogenetic reconstructions based on sequencing of the control mtDNA region, which reflects mutual inconsistency of different systems of inheritance.     

Genetic and taxonomic diversity of the house mouse Mus musculus from the asian part of the former Soviet Union

Genetic diversity of the house mouse Mus musculus from 12 local populations (n = 65) of the central and eastern parts of the former Soviet Union was examined using RAPD-PCR. About 400 loci were identified, encompassing approximately 500 kb of the mouse genome. Genetic diversity was assessed using NTSYS, POPGENE, TFPGA, and TREECON software programs. In general, the house mouse sample from the regions examined was characterized by moderate genetic variation: polymorphism P = 95.6%, P99 = 60.7%, P95 = 24.2%; heterozygosity H = 0.089; the mean observed number of alleles n(a) = 1.97; effective number of alleles n = 1.13; intrapopulation differentiation deltaS = 0.387; gene diversity h = 0.09. Individual local populations displayed different levels of genetic isolation: the genetic subdivision index G(st) varied from 0.086 to 0.324 at gene flow Nm varying from 5.3 to 1.05, while the interpopulation genetic distance D(N) ranged from 0.059 to 0.186. Most of the genetic diversity of the total sample resided within the local populations: H(S) = 0.6, total gene diversity H(T) = 0.09. The exact test for differentiation, however, did not confirm the affiliation of all the mice examined to one population: chi2 = 1446, d.f. = 724, P = 0.000. Molecular markers specific to four subspecies (musculus, castaneus, gansuensis, and wagneri) were identified. Moreover, in some cases the populations and individual animals exhibited traits of different subspecies, suggesting their introgressive hybridization. It was demonstrated that the house mouse fauna on the territories investigated was characterized by the prevalence of musculus-specific markers, while gansuensis-specific markers ranked second. The castaneus-specific markers were highly frequent in the Far East, but almost absent in Central Asia, where wagneri-specific markers were detected. It was suggested that house mice from Turkmenistan could belong to one of the southern subspecies, which had not deeply penetrated into the Asian fauna of the former Soviet Union. In phenogenetic (UPGMA) and phylogenetic (NJ) reconstructions this form with the high bootstrap support was placed at the tree base, while the isolation of other clusters was not statistically significant. It is thus likely that the house mice from Turkmenistan are closest to the ancestral form of the genus Mus on the territory of the former Soviet Union.     

Population differentiation and gene flow revealed by microsatellite DNA markers in the house mouse (Mus musculus castaneus) in Taiwan

We analyzed population subdivision and gene flow of the Southeast Asian house mouse (Mus musculus castaneus) in Taiwan by using six microsatellite DNA markers. Seven populations of the house mouse (187 individuals), including one from Fukien Province in southeastern China, which is separated from Taiwan by the Taiwan Strait, were analyzed in this study. The overall polymorphic level at the six loci was high (He = 0.76) although individual populations varied in their levels of heterozygosity (He = 0.35-0.83). For the populations within Taiwan, there was no evidence of isolation by distance and the level of gene flow was not (inversely) correlated to geographic distances. Gene flow was estimated to be higher across the Taiwan Strait than within the island of Taiwan. These observations of gene flow cannot be understood unless in the context of the historical human settlements and agricultural expansion, and the commensal habits of the species. We also discussed the causes of population subdivision and genetic variation among populations in terms of ecological characteristics of the house mouse in Taiwan.     

Town Mouse, Country Mouse: adaptation and adaptability in Mus domesticus (M. musculus domesticus)

The generally accepted idea that the house mouse is a single, world-wide species which owes its success largely to commensalism with man is wrong. There are at least five European and two Asian species lumped together under the name Mus musculus, plus another fourteen Asian species in the same genus. The house mouse of western Europe is the one that has been introduced to the Americas and Australasia, as well as being domesticated in the laboratory and ‘fancy’ strains; it is properly described as Mus domesticus. A complication of this particular species is the existence of chromosomal races involving the fusion of pairs of chromosomes, apparently at random. These races seem to be reproductively isolated from normal (2n = 40) mice. They have been described in southern Europe and northern Britain. Genetical studies of wild-living mice have shown the operation of powerful natural selection, contrary to earlier assumptions that most of the polymorphic variation in the species (especially that revealed by electrophoresis) was neutral. The effects of such selection are reduced (but not eliminated) by the deme structure of established mouse populations; this social structure is much less rigid than some laboratory experiments have suggested, because of opportunism by individual mice in replacing dead or debilitated animals, and filling new niches as these become available. Virtually every mouse population is unique, since a population tends to be founded by a small group of animals drawn from a genetically variable ancestral population. This differentiation has allowed laboratory workers to develop inbred strains with characteristic properties; it has also resulted in over 130 sub-species being described from wild caught animals. A substantial proportion of these latter have probably arisen by instant sub-speciation through the founder effect. This is well illustrated by the mice of the Faroe islands, which are often quoted as standard examples of extremely rapid evolution. The adaptive properties of the house mouse that have made it such an effective pest and such a good laboratory animal have enabled it to colonize habitats as different as Antarctic tundra and tropical atolls. The species is an ideal one for the general biological task of dissecting the traits that contribute to this adaptability; the material is largely available for this task in the diversity of local forms established in different habitats and characterized genetical varieties maintained in the laboratory. More is known about M. domesticus than any other mammal, except possibly man; the time is ripe for fusing laboratory work on reproduction, mortality, and behaviour with the information increasingly coming from field studies of wild-living animals.     

The dynamic of the t-haplotype in wild populations of the house mouse Mus musculus domesticus in Israel

The t-haplotype, a variant of the proximal part of the mouse chromosome 17, is composed of at least four inversions and is inherited as a single genetic unit. The haplotype causes embryonic mortality or male sterility when homozygous. Genes within the complex are responsible for distortion of Mendelian transmission ratio in males. Thus, the t-haplotype in heterozygous males is transferred to over 95% of the progeny. We examined the dynamic and behavior of the t-haplotype in wild populations of the house mouse in Israel. The Israeli populations show high frequency (15%–20%) of both partial and complete t-carrying mice, supporting the suggestion that the t-complex evolved in the M. domesticus line in the Israeli region. In one population that had the highest frequency of t-carrying individuals, we compared the level of gene diversity between t-carrying and normal mice in the marker’s loci: H-2 locus of the major histocompatibility complex (MHC) on the t-haplotype of chromosome 17, three microsatellites on other chromosomes, and the mitochondrial D-loop. Genetic variability was high in all tested loci in both t and (+) mice. All t mice carried the same chromosome and showed the same H-2 haplotype. While t-carrying mice showed significant H-2 heterozygotes access, (+) mice expressed significant H-2 heterozygote deficiency. There were no differences in the level of gene diversity between t and (+) mice in the other loci. Heterozygosity level at the MHC may be an additional factor in the selective forces balancing the t-haplotype polymorphism.     

Genetic characterisation of Mus musculus and related forms from India.

The present study reports the biochemical genetic profile of commensal forms of Indian wild house mouse populations Mus musculus from ten localities as well as other species of genus Mus, M. platythrix, M. booduga and M. terricolor III. Extreme polymorphism seen by the presence of a large number of variants and novel alleles in these animals indicates that the Indian M. musculus holds considerable potential for development of useful models for biomedical research.     

Impact of introduced house mice (Mus musculus) on burrowing seabirds on Steeple Jason and Grand Jason Islands,Falklands, South Atlantic

Whilst there is good evidence for negative impacts of introduced rat species on island ecosystems, the effects of house mice (Mus musculus) are generally less well documented. In some situations, introduced house mice can exert severe impacts, particularly where this is the only introduced mammal. Here, we examine the distribution, relative abundance and breeding success of small burrowing seabirds on Steeple Jason Island, Falklands, in relation to habitat types and the distribution of house mice which is the sole introduced mammal species, and we make comparisons with seabird distribution and densities on the neighbouring island of Grand Jason where mice are absent. Grey-backed storm-petrel (Garrodia nereis) and Wilson’s storm-petrel (Oceanites oceanicus), which due to their extremely small size are likely to be the most vulnerable to mouse predation, were considerably more abundant on mouse-free Grand Jason than on Steeple Jason. Grey-backed storm-petrel, which are typically associated with tussac grass, avoided this habitat on Steeple Jason where it is associated with high levels of house mouse activity (assessed from the proportion of wax baits gnawed overnight), whereas on mouse-free Grand Jason, there was no such avoidance. Wilson’s storm-petrel nesting on Steeple Jason suffered high rates of egg and chick loss. Whilst we found evidence for detrimental impacts of house mice on the two small storm-petrel species, there was no relationship between relative mouse activity levels and the distribution or abundance of the larger thin-billed Prion (Pachyptila belcheri).     

Of mice and 'convicts': origin of the Australian house mouse, Mus musculus

The house mouse, Mus musculus, is one of the most ubiquitous invasive species worldwide and in Australia is particularly common and widespread, but where it originally came from is still unknown. Here we investigated this origin through a phylogeographic analysis of mitochondrial DNA sequences (D-loop) comparing mouse populations from Australia with those from the likely regional source area in Western Europe. Our results agree with human historical associations, showing a strong link between Australia and the British Isles. This outcome is of intrinsic and applied interest and helps to validate the colonization history of mice as a proxy for human settlement history.     

Genetic and Taxonomic Diversity of the House Mouse Mus musculus from the Asian Part of the Former Soviet Union

Genetic diversity of the house mouse Mus musculus from 12 local populations (n = 65) of the central and eastern parts of the former Soviet Union was examined using RAPD–PCR. About 400 loci were identified, encompassing approximately 500 kb of the mouse genome. Genetic diversity was assessed using NTSYS, POPGENE, TFPGA, and TREECON software programs. In general, the house mouse sample from the regions examined was characterized by moderate genetic variation: polymorphism P = 95.6%, P ₉₉ = 60.7%, P ₉₅ = 24.2%; heterozygosity H = 0.089; the mean observed number of alleles n _a = 1.97; effective number of alleles n _e = 1.13; intrapopulation differentiation _S = 0.387; gene diversity h = 0.09. Individual local populations displayed different levels of genetic isolation: the genetic subdivision index G _st varied from 0.086 to 0.324 at gene flow Nm varying from 5.3 to 1.05, while the interpopulation genetic distance D _N ranged from 0.059 to 0.186. Most of the genetic diversity of the total sample resided within the local populations: H _S = 0.06, total gene diversity H _T = 0.09. The exact test for differentiation, however, did not confirm the affiliation of all the mice examined to one population: ² = 1446, d.f. = 724, P = 0.000. Molecular markers specific to four subspecies (musculus, castaneus, gansuensis, and wagneri) were identified. Moreover, in some cases the populations and individual animals exhibited traits of different subspecies, suggesting their introgressive hybridization. It was demonstrated that the house mouse fauna on the territories investigated was characterized by the prevalence of musculus-specific markers, while gansuensis-specific markers ranked second. The castaneus-specific markers were highly frequent in the Far East, but almost absent in Central Asia, where wagneri-specific markers were detected. It was suggested that house mice from Turkmenistan could belong to one of the southern subspecies, which had not deeply penetrated into the Asian fauna of the former Soviet Union. In phenogenetic (UPGMA) and phylogenetic (NJ) reconstructions this form with the high bootstrap support was placed at the tree base, while the isolation of other clusters was not statistically significant. It is thus likely that the house mice from Turkmenistan are closest to the ancestral form of the genus Mus on the territory of the former Soviet Union.     

Natural hybridization between 2 sympatric species of mice, Mus musculus domesticus L. and Mus spretus Lataste

Using protein loci and DNA markers, we show by a multilocus genetic analysis that certain populations of the two sympatric mouse species Mus musculus domesticus and Mus spretus show clear signs of partial introgression. Given the sterility of F1 males and the known partial genetic incompatibilities between the genomes of the two species, our finding does not invalidate the biological species complex, but allows to think that very limited genetic exchanges remain possible even long after the divergence of taxa. This may have some consequences on the dynamics of certain kinds of invasive or advantageous DNAs like transposable elements or pathogen resistance genes.     

Allozyme variability and the population genetic structure of the mice Apodemus agrarius,Mus musculus,and Sylvaemus uralensis (Rodenita,Muridae) in Western Siberia

Of the three mouse species inhabiting Western Siberia, the striped field mouse is characterized by the highest level of genetic variation, a uniform distribution of polymorphism indicators, lower values of genetic differentiation, and higher values of gene flow, as compared to the house mouse and pygmy wood mouse. The house mouse populations have abrupt changes in the parameters of protein polymorphism in different localities. This is due to the considerable spatial dissociation of the cities of Siberia and the differing histories of their settlement. Inhabitation of an urban area leads to the partitioning of striped wood mouse populations into groups that considerably differ in allele frequencies and genetic variation indices. These changes are not related to the degree of urbanization and are determined by genetic drift. Some characteristics of these groups, like reduced variability, heterozygote deficit, and deviation from the Hardy-Weinberg equilibrium, limit their adaptive potential and make them dependent on the populations of inter-settlement territories.     

Broad-scale latitudinal patterns of genetic diversity among native European and introduced house sparrow (Passer domesticus) populations

Introduced species offer unique opportunities to study evolution in new environments, and some provide opportunities for understanding the mechanisms underlying macroecological patterns. We sought to determine how introduction history impacted genetic diversity and differentiation of the house sparrow (Passer domesticus), one of the most broadly distributed bird species. We screened eight microsatellite loci in 316 individuals from 16 locations in the native and introduced ranges. Significant population structure occurred between native than introduced house sparrows. Introduced house sparrows were distinguished into one North American group and a highly differentiated Kenyan group. Genetic differentiation estimates identified a high magnitude of differentiation between Kenya and all other populations, but demonstrated that European and North American samples were differentiated too. Our results support previous claims that introduced North American populations likely had few source populations, and indicate house sparrows established populations after introduction. Genetic diversity also differed among native, introduced North American, and Kenyan populations with Kenyan birds being least diverse. In some cases, house sparrow populations appeared to maintain or recover genetic diversity relatively rapidly after range expansion (<50 years; Mexico and Panama), but in others (Kenya) the effect of introduction persisted over the same period. In both native and introduced populations, genetic diversity exhibited large-scale geographic patterns, increasing towards the equator. Such patterns of genetic diversity are concordant with two previously described models of genetic diversity, the latitudinal model and the species diversity model.     

Microhabitat use by the house mouseMus musculus in an urban area

Understanding some aspects of the ecology of the house mouseMus musculus Linnaeus, 1758 in an urban area may be crucial to decide materials or strategies for pest control. The aim of this study was to examine microhabitat use byM. musculus in vacant lots in the urban area of Río Cuarto, Córdoba, Argentina. We livetrapped M. musculus in five vacant lots in summer and autumn of 2006, and in four vacant lots in summer and autumn of 2007. Variables influencing the use and not-use of trapping stations by the house mouse by season were identified with a logistic regression.M. musculus presence was closely associated with vegetation variables. In three of four analyzed seasons, the house mouse presence was positively associated with high values of vegetation volume and negatively associated with traps located close to walls. To control mouse presence in vacant lots, it would be important to minimize habitat complexity through the maintenance of a short vegetation cover and the avoidance of the important plant species growth forM. musculus.     

Origin of the house mice (superspecies complex Mus musculus sensu lato) from the Transcaucasian region: A new look at dispersal routes and evolution

We analyzed our results and literature evidence on variability of nuclear protein genes in 39 populations of eight synanthropic and wild species of house mice (superspecies complexes Mus musculus and M. spicilegus) from Transcaucasia, Eastern and Western Europe, Near and Middle East, Central, South, and East Asia, and Cuba. These data were for the first time ever combined into a single database by unification of nomenclature of 21 loci examined by different authors in 39 populations. Analysis of geographical allele distribution have shown that populations of domestic Transcaucasian mice are close to Indo-Pakistani populations of form oriental of the species M. castaneus, which preserved a high level of ancestral polymorphism. We concluded that a very heterogeneous, rich gene pool of house mice from Transcaucasia could not develop only by secondary contacts of differentiated M. musculus s. str. and M. domesticus forms, since it is similar to the ancestral gene pool of the superspecies complexes M. musculus and M. spicilegus. In this context, unique characteristics of some Central Asian populations were examined; these populations may have served as a "transit station" in the dispersal of synanthropic house mice forms. We suggest that the Transcaucasian populations are genealogically closely related to an early Near East form of M. musculus, which, as M. domesticus and M. castaneus, split from the common ancestor and preserved nondifferentiated pool of ancestral alleles of protein genes. This hypothesis admits the involvement of differentiated species M. musculus s. str. and M. domesticus in the ultimate formation of the gene pool of Transcaucasian house mice. Apparently, these populations resulted from alternation and (or) "overlapping" of different evolutionary processes. A scenario suggesting that hybrid events having occurred in Transcaucasia at different times, were "superposed" on the gene pool of the ancient autochtonous population of house mice from this region seems most plausible. Analysis of allozyme variability in the modern Transcaucasian Mus populations could not always distinguish between ancestral polymorphism and hybridization consequences.     

小家鼠和实验小鼠遗传特性的比较研究

本文用同工酶电泳法、微量细胞毒法和免疫双向扩散法对我国4个动物地理区的6个采集点的156个小家鼠(Mus musculus)进行了遗传特性的调查。结果发现:在全部被测的13个位点中,小家鼠在7个位点上存在着多种实验小鼠中罕见的基因组成;而不同动物地理区和亚区的小家鼠的遗传特性又各不相同。从而指出将小家鼠的特有基因导入实验小鼠,培育新品系的重大意义。     

Organ specific expression of esterase-6 in the house mouse,Mus musculus

Summary Esterase-6 in fresh homogenates of heart muscle and testis of the house mouse shows a two band (C allele) or three band (A allele) pattern in disc electrophoresis. These primary bands generated a series of secondary bands upon lowering the pH of the homogenates, and the secondary pattern, possibly resulting from partial proteolysis, was seen in varying degrees in fresh homogenates from a range of organs. Interrelationships between the primary and secondary bands were demonstrated by isoelectric focusing. The esterase-6 content of twenty different organ homogenates was estimated from electrophoretic gels, and a high level of this enzyme was observed in those organs most actively involved in fat metabolism. The possible participation of esterase-6 in fatty acid utilization is discussed. Similarities between esterase-6 of the house mouse and esterase-4 of the rat were demonstrated, further strengthening the view that these enzymes are homologous.Supported by the Deutsche Forschungsgemeinschaft (SFB 46)This is communication no 36 of a research program devoted to the cellular distribution, genetics, and regulation of non-specific esterases     

Nonspecific esterases of Mus musculus

Seventeen genes controlling the expression of carboxylic ester hydrolases, commonly known as esterases, have been identified in the mouse Mus musculus. Seven esterase loci are found on chromosome 8, where two clusters of esterase loci occur. It seems probable that the genes within these clusters have arisen from a common ancestral gene by tandem duplication. Close linkage of esterase genes is also found in the rat, rabbit, and prairie vole. Some mouse esterases appear to be homologous with certain human esterases. The function of these nonspecific enzymes is still unknown.