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accumulation of rare sex chromosome rearrangements in the african pygmy mouse, mus (nannomys) minutoides: a whole-arm reciprocal translocation (wart) involving an x-autosome fusion.although sex chromosomes are generally the most conserved elements of the mammalian karyotype, those of african pygmy mice show three extraordinary deviations from the norm: (a) asynaptic sex chromosomes, (b) multiple sex-autosome fusions, and (c) modifications of sex determination in some populations/species. in this study we identified, in two sex-reversed females of mus (nannomys) minutoides, a fourth rare sex chromosome change: a spontaneous whole-arm reciprocal translocation (wart) between ...200717285252
observations on the food habits of some african rodents.food habits of four common species of african rodents: the giant rat (cricetomys gambianus), the black house rat (rattus rattus), the multimammate rat (mastomys natalensis) and the pygmy mouse (mus minutoides) were studied on the basis of stomach content analysis, habitat sampling and experimental trials with caged animals. vegetable items (especially grass, grains and tubers) formed the bulk of the food of all the species. oil-palm nuts and kernels were also common in the guts of c. gambianus a ...19807323341
survey of hymenolepis spp. in pet rodents in italy.we carried out the first survey of hymenolepis spp. infection in pet rodents in italy. fresh fecal samples were collected from 172 pet rodents as follows: guinea pigs (cavia porcellus; n = 60), squirrels (callosciurus finlaysonii, callosciurus prevosti, tamias striatus, tamias sibiricus, sciurus calorinensis; n = 52), hamsters (phodopus campbelli, mesocricetus auratus; n = 30), chinchillas (chinchilla lanigera; n = 13), rats (rattus norvegicus; n = 10), and mice (mus minutoides; n = 7). these an ...201526290218
novel postentry resistance to akv ecotropic mouse gammaretroviruses in the african pygmy mouse, mus minutoides.cells of mus minutoides, an african pygmy mouse of the subgenus nannomys, are susceptible to ecotropic moloney and friend mouse leukemia viruses (mlvs) but not to akv-type mlvs. transfected ma139 ferret cells expressing the mcat-1 cell surface receptor, with the mincat-1 substitutions k222q and v233l, did not restrict akv mlv. the resistance of m. minutoides cells to akv mlv was not relieved by inhibitors of glycosylation or by the introduction of nih 3t3 mcat-1. resistance is thus not mediated ...200818417580
the testis-determining gene, sry, exists in multiple copies in old world rodents.sry is a unique gene on the y chromosome in most mammalian species including the laboratory mouse, mus musculus, and the closely related european wild mouse species m. spicilegus, m. macedonicus, and m. spretus. in contrast, sry is present in 2-6 copies in the more distantly related asian mouse species m. caroli, m. cervicolor, and m. cookii and in 2-13 copies in the related murid species pyromys saxicola, coelomys pahari, nannomys minutoides, mastomys natalensis, and rattus norvegicus. copy num ...19947698639
genetic identification of kodoko virus, a novel arenavirus of the african pigmy mouse (mus nannomys minutoides) in west africa.genetic evidence of a novel arenavirus species related to but distinct from lymphocytic choriomeningitis virus (lcmv) was obtained from a rodent belonging to an endemic african subgenus of mus (nannomys). the phylogenetic position among old world arenaviruses of this new arenavirus, named kodoko virus, was reconstructed based on l and np genes sequences. the finding of an old world arenavirus related to lcmv outside the known geographical range of lcmv in a novel rodent species reveals new insig ...200717382366
recent isolations of lassa virus from nigerian rodents.rodents were trapped in the benue-plateau and north-eastern states of nigeria where lassa fever had been reported in previous years. eight lassa virus strains were isolated from tissues and blood of rodents identified in the field as being of 3 different species: mastomys natalensis, rattus rattus, and mus minutoides. all the infected rodents were collected in village habitats. these isolations indicate the presence of lassa virus in wild rodents in nigeria during periods when no human infection ...19751085216
genetic variation in mouse apolipoprotein a-iv due to insertion and deletion in a region of tandem repeats.we have detected three unique apolipoprotein a-iv (apoa-iv) charge isoforms in strains of commensal mice. the cdna sequences for one representative of each isoform (mus domestesticus strains c57bl/6j and 129/j and mus castaneus) revealed a polymorphism within a series of four imperfect repeats encoding the sequence glu-gln-ala/val-gln. insertions or deletions of 12 nucleotides within this repetitive region have given rise to three genotypes characterized by three (129), four (c57bl/6), or five ( ...19911648102
pigs are the most important animal reservoir for tunga penetrans (jigger flea) in rural nigeria.we examined the domestic animals and rodents in a community in rural nigeria. of the 133 animals examined, 29 (21.8%) were infested, the highest prevalence of infestation and highest parasite load was found in the pigs (prevalence 54.8%, median = nine embedded parasites), followed by dogs (45.5%; median = 4), rattus rattus (29.4%; median = 2) and mus minutoides (15.4%; median = 1.5). of all the tungiasis lesions identified 83% were found in pigs. our data confirm that tungiasis is a zoonotic dis ...200818820191
a novel sex determination system in a close relative of the house mouse.therian mammals have an extremely conserved xx/xy sex determination system. a limited number of mammal species have, however, evolved to escape convention and present aberrant sex chromosome complements. in this study, we identified a new case of atypical sex determination in the african pygmy mouse mus minutoides, a close evolutionary relative of the house mouse. the pygmy mouse is characterized by a very high proportion of xy females (74%, n = 27) from geographically widespread southern and ea ...201020007182
phylogenomics of the genus mus (rodentia; muridae): extensive genome repatterning is not restricted to the house mouse.the house mouse (mus musculus) is universally adopted as the mammalian laboratory model, and it is involved in most studies of large-scale comparative genomics. paradoxically, this taxon is rarely the index species for evolutionary analyses of genome architecture owing to its highly rearranged karyotype. to unravel the origin and nature of this extensive repatterning genome, we performed a multidirectional chromosome painting study of representative species within the genus mus. however, the lat ...200617015352
patterns of divergence during evolution of alpha 1-proteinase inhibitors in mammals.alpha 1-proteinase inhibitor (alpha 1-pi), a member of the serine proteinase inhibitor superfamily, has a primary role in controlling neutrophil elastase activity within the mammalian circulation. several studies have indicated that the reactive center region of alpha 1-pi, the amino acid sequence of which is critical to recognition of and binding to target proteinases, is highly divergent within and among species. this appears to be a consequence of accelerated rates of evolution that may have ...19968587500
helminths collected from imported pet murids, with special reference to concomitant infection of the golden hamsters with three pinworm species of the genus syphacia (nematoda: oxyuridae).a total of 210 individuals of 13 species belonging to 4 subfamilies of muridae imported into japan as pets were examined; 5 species of syphacia (nematoda: oxyuridae), aspiculuris tetraptera (nematoda: heteroxynematidae), and rodentolepis nana (cestoidea: hymenolepididae) were collected. concurrent infection with 3 pinworm species, syphacia mesocriceti, syphacia stroma, and syphacia peromysci, was recorded for the first time in the golden hamster, mesocricetus auratus. syphacia mesocriceti was al ...200818605784
anatomical and molecular analyses of xy ovaries from the african pygmy mouse mus minutoides.the african pygmy mouse mus minutoides is characterized by the presence of a high proportion of fertile xy females in natural populations. this species displays 2 morphologically different x chromosomes: the ancestral x and a shorter one designated as x*, feminizing the x*y individuals. this strongly suggests that in the presence of an x* chromosome, the male differentiation program is not activated despite a functional y chromosome. in this study, we compared the histology of the adult ovaries ...201425359508
reduced activity of sry and its target enhancer sox9-tesco in a mouse species with x*y sex reversal.in most eutherian mammals, sex determination is governed by the y-linked gene sry, but in african pygmy mice mus minutoides, sry action is overridden by a variant x chromosome (x*), yielding x*y females. we hypothesized that x*y sex reversal may be underpinned not only by neomorphic x chromosome functionality, but also by a compromised sry pathway. here, we show that neither m. minutoides sry nor its target, the sox9-tesco enhancer, had appreciable transcriptional activity in in vitro assays, co ...201728155866
sex reversal induces size and performance differences among females of the african pygmy mouse, mus minutoides.differences in biological performance, at both intra- and inter-specific levels, have often been linked to morphology but seldom to behavioural or genotypic effects. we tested performance at the intraspecific level by measuring bite force in the african pygmy mouse, mus minutoides. this species displays an unusual sex determination system, with sex-reversed, x*y females carrying a feminizing x* chromosome. x*y females cannot be differentiated from xx females based on external or gonadal morpholo ...201728566353
x inactivation in a mammal species with three sex chromosomes.x inactivation is a fundamental mechanism in eutherian mammals to restore a balance of x-linked gene products between xy males and xx females. however, it has never been extensively studied in a eutherian species with a sex determination system that deviates from the ubiquitous xx/xy. in this study, we explore the x inactivation process in the african pygmy mouse mus minutoides, that harbours a polygenic sex determination with three sex chromosomes: y, x, and a feminizing mutant x, named x*; fem ...201729256059
mitochondrial dna and karyotypic data confirm the presence of mus indutus and mus minutoides (mammalia, rodentia, muridae, nannomys) in botswana.we use a combination of cytochrome b sequence data and karyological evidence to confirm the presence of mus indutus and mus minutoides in botswana. our data include sampling from five localities from across the country, including one site in northwestern botswana where both species were captured in syntopy. additionally, we find evidence for two mitochondrial lineages of m. minutoides in northwestern botswana that differ by 5% in sequence variation. also, we report that m. minutoides in botswana ...201324363588
foraging in space and time structure an african small mammal community.we used live-trapping and foraging to test for the effect of habitat selection and diet on structuring a community of six small mammals and one bird within the soutpansberg, south africa. we established grids that straddled adjacent habitats: woodland, rocky hillside, and grassland. trapping and foraging were used to estimate abundance, habitat use, and species-specific foraging costs. the species with the highest abundance and foraging activity in a habitat, activity time, or food was considere ...201424648024
xy females do better than the xx in the african pygmy mouse, mus minutoides.all therian mammals have a similar xy/xx sex-determination system except for a dozen species. the african pygmy mouse, mus minutoides, harbors an unconventional system in which all males are xy, and there are three types of females: the usual xx but also xx* and x*y ones (the asterisk designates a sex-reversal mutation on the x chromosome). the long-term evolution of such a system is a paradox, because x*y females are expected to face high reproductive costs (e.g., meiotic disruption and loss of ...201424611447
insights into the evolutionary history of the x-linked sex reversal mutation in mus minutoides: clues from sequence analyses of the y-linked sry gene.the african pygmy mouse, mus minutoides, is one of the very few mammal species that deviates from the classical mammalian xx/xy sex chromosome system by presenting a high proportion of fully fertile sex-reversed females. since the still unknown sex reversal mutation is x-linked (x*), they are designated as x*y females. until now, x*y females had only been identified in southern africa, but data were lacking for the rest of the vast sub-saharan distribution range of this species. in this study, t ...201323817242
a phylogeographic survey of the pygmy mouse mus minutoides in south africa: taxonomic and karyotypic inference from cytochrome b sequences of museum specimens.the african pygmy mice (mus, subgenus nannomys) are a group of small-sized rodents that occur widely throughout sub-saharan africa. chromosomal diversity within this group is extensive and numerous studies have shown the karyotype to be a useful taxonomic marker. this is pertinent to mus minutoides populations in south africa where two different cytotypes (2n = 34, 2n = 18) and a modification of the sex determination system (due to the presence of a y chromosome in some females) have been record ...201424905736
cytogenetics of a new cytotype of african mus (subgenus nannomys) minutoides (rodentia, muridae) from kenya: c- and g- banding and distribution of (ttaggg)n telomeric sequences.we present the results of a cytogenetic study on mus (nannomys) minutoides from kenya by means of c- and g- banding and in-situ fluorescence hybridization (fish) to localize the telomeric sequences. the karyotype is characterized by the occurrence of several rb chromosomes rb(1.x), rb(1.y). rb(2.17), rb(3.13), rb(4.10), rb(5.11), rb(6.7), rb(8.12), not previously described for this species. this finding suggests a high level of chromosomal diversification, which means it is possible to consider ...200616823620
cytogenetic analyses of chromosomal rearrangements in mus minutoides/musculoides from north-west zambia through mapping of the telomeric sequence (ttaggg)n and banding techniques.three specimens of m. minutoides/musculoides from zambia were cytogenetically studied through g- and c-banding, dapi staining and fluorescence in-situ hybridization (fish) with a (ttaggg)n telomeric sequence. biarmed chromosomes were identified according to the current nomenclature as follows: rb(2.7), rb(3.12), rb(4.5), rb(6.8), rb(9.16), and the sex chromosomes rb(1.x), rb(1.y) and rb(1.xd), originated from the deleted x chromosome. one female showed the diploid number 2n = 24; in the two othe ...200212296522
exon-specific gene correction (conversion) during short evolutionary periods: homogenization in a two-gene family encoding the beta-chain constant region of the t-lymphocyte antigen receptor.the two genes encoding the beta-chain constant region of the t-lymphocyte antigen receptor appear to have undergone gene conversion in a number of species, including wild and laboratory mice. to examine the frequency of such events during short evolutionary periods, we have characterized the corresponding genes from an african pygmy mouse, mus minutoides. sequence analysis indicates that exon 1 regions from these genes have undergone conversion events independent of those observed in other mouse ...19921532437
a new cytotype of the african pygmy mouse mus minutoides in eastern africa. implications for the evolution of sex-autosome translocations.the african pygmy mice (genus mus, subgenus nannomys) are recognized for their highly conserved morphology but extensive chromosomal diversity, particularly involving sex-autosome translocations, one of the rarest chromosomal rearrangements among mammals. it has been shown that in the absence of unambiguous diagnostic morphological traits, sex-autosome translocations offer accurate taxonomic markers. for example, in mus minutoides, irrespective of the diploid number (which ranges from 2n = 18 to ...201425159220
masculinised behaviour of xy females in a mammal with naturally occuring sex reversal.most sex differences in phenotype are controlled by gonadal hormones, but recent work on laboratory strain mice that present discordant chromosomal and gonadal sex showed that sex chromosome complement can have a direct influence on the establishment of sex-specific behaviours, independently from gonads. in this study, we analyse the behaviour of a rodent with naturally occurring sex reversal: the african pygmy mouse mus minutoides, in which all males are xy, while females are of three types: xx ...201626964761
molecular surveillance and phylogenetic analysis of old world arenaviruses in zambia.in order to survey arenaviruses in the republic of zambia, we captured 335 rodents from three cities between 2010 and 2011. eighteen luna virus (lunv) and one lymphocytic choriomeningitis virus (lcmv)-related virus rnas were detected by one-step rt-pcr from mastomys natalensis and mus minutoides, respectively. four lunv strains and one lcmv-related virus were isolated, and the whole genome nucleotide sequence was determined by pyrosequencing. phylogenetic analyses revealed that the lunv clade co ...201222815269
mitochondrial and chromosomal insights into karyotypic evolution of the pygmy mouse, mus minutoides, in south africa.the african pygmy mouse, mus minutoides, displays extensive robertsonian (rb) diversity. the two extremes of the karyotypic range are found in south africa, with populations carrying 2n = 34 and 2n = 18. in order to reconstruct the scenario of chromosomal evolution of m. minutoides and test the performance of rb fusions in resolving fine-scale phylogenetic relationships, we first describe new karyotypes, and then perform phylogenetic analyses by two independent methods, using respectively mitoch ...201020582567
lassa serology in natural populations of rodents and horizontal transmission.lassa virus causes hemorrhagic fever in west africa. previously, we demonstrated by pcr screening that only the multimammate mouse, mastomys natalensis, hosts lassa virus in guinea. in the present study, we used the same specimen collection from 17 villages in coastal, upper, and forest guinea to investigate the lassa virus serology in the rodent population. the aim was to determine the dynamics of antibody development in m. natalensis and to detect potential spillover infections in other rodent ...201425229705
nuclear organization of cholinergic, putative catecholaminergic, serotonergic and orexinergic systems in the brain of the african pygmy mouse (mus minutoides): organizational complexity is preserved in small brains.this study investigated the nuclear organization of four immunohistochemically identifiable neural systems (cholinergic, catecholaminergic, serotonergic and orexinergic) within the brain of the african pygmy mouse (mus minutoides). the african pygmy mice studied had a brain mass of around 275 mg, making these the smallest rodent brains to date in which these neural systems have been investigated. in contrast to the assumption that in this small brain there would be fewer subdivisions of these ne ...201222554581
reciprocal size-effect relationship of the key residues in determining regio- and stereospecificities of dhea hydroxylase activity in p450 2a5.collectively, the p450 2a4/2a5 system hyrdoxylates dhea in at least three positions (7alpha, 7beta, and 2alpha). an individual p450, however, exhibits high specificity to one of these products. using site-directed mutagenesis of mp450 2a5 from the wild mouse mus minutoides and bacterial expression, we have associated the function of residues 117, 209, and 481 with the respective specificity observed in each p450. ala at position 117 determines the 7beta-hydroxylase activity, whereas val at this ...19979115996
one skull to rule them all? descriptive and comparative anatomy of the masticatory apparatus in five mouse species.murine rodents display a unique cranial morphology and masticatory musculature. yet detailed myological descriptions are scarce, especially considering the great diversity of the subfamily and the use of the house mouse and brown rat as model organisms. the masticatory musculature in these two species has been thoroughly described, which allows comparisons with other wild species. description and comparison of a wide range of species constitutes a necessary step to fully understand how ecologica ...201830117607
sex chromosome quadrivalents in oocytes of the african pygmy mouse mus minutoides that harbors non-conventional sex chromosomes.eutherian mammals have an extremely conserved sex-determining system controlled by highly differentiated sex chromosomes. females are xx and males xy, and any deviation generally leads to infertility, mainly due to meiosis disruption. the african pygmy mouse (mus minutoides) presents an atypical sex determination system with three sex chromosomes: the classical x and y chromosomes and a feminizing x chromosome variant, called x*. thus, three types of females coexist (xx, xx*, and x*y) that all s ...201930919035
meiosis reveals the early steps in the evolution of a neo-xy sex chromosome pair in the african pygmy mouse mus minutoides.sex chromosomes of eutherian mammals are highly different in size and gene content, and share only a small region of homology (pseudoautosomal region, par). they are thought to have evolved through an addition-attrition cycle involving the addition of autosomal segments to sex chromosomes and their subsequent differentiation. the events that drive this process are difficult to investigate because sex chromosomes in almost all mammals are at a very advanced stage of differentiation. here, we have ...202033180767
improved mitochondrial coupling as a response to high mass-specific metabolic rate in extremely small mammals.mass-specific metabolic rate negatively co-varies with body mass from the whole-animal to the mitochondrial levels. mitochondria are the mainly consumers of oxygen inspired by mammals to generate atp or compensate for energetic losses dissipated as the form of heat (proton leak) during oxidative phosphorylation. consequently, atp synthesis and proton leak compete for the same electrochemical gradient. because proton leak co-varies negatively with body mass, it is unknown whether extremely small ...202032041806
correction: sex reversal induces size and performance differences among females of the african pygmy mouse, mus minutoides (doi: 10.1242/jeb.157552). 201829802175
widespread arenavirus occurrence and seroprevalence in small mammals, nigeria.lassa fever, killing thousands of people annually, is the most reported viral zoonotic disease in nigeria. recently, different rodent species carrying diverse lineages of the lassa virus (lasv) in addition to a novel mobala-like genetic sequence were detected within the country. here, screening 906 small mammal specimens from 11 localities for igg antibodies and incorporating previous pcr detection data involving the same populations, we further describe arenavirus prevalence across nigeria in r ...201830005641
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