Allozyme Variability among Populations of Three Species of Brush-Furred Mice (Lophuromys,Rodentia, Muridae) from the Bale Mountains National Park (Ethiopia)

Allozyme variability was examined in populations of three endemic species of the species complex Lophuromys flavopunctatussensu lato: L. chrysopus, L. brevicaudus, and L. melanonyx. These species replace each other in adjacent altitudinal belts of the Bale Massif in Ethiopia. A deficit of heterozygotes at several loci was found in most samples of all species studied. Moreover, the samples included animals homozygous for two or three minor alleles and heterozygous for alleles that are rare and unique for the given species. It is suggested that the Bale Massif are inhabited by numerous genetically isolated populations of eachLophuromys species, which exchange genes at an extremely low rate. Genotypic disequilibrium observed in most samples is explained by the fact that most sampling localities comprise ranges of two and more micropopulations. In our view, microgeographic subdivision of the populations is caused by recurrent fragmentation of habitats during the Pleistocene glaciation of the Bale Massif and subsequent prolonged isolation of local populations. Gene drift accompanying these processes resulted in high genetic differentiation of the local populations, which probably persisted until the present. Geographical isolation of the Bale Massif, its uniquely diverse ecological conditions, and extraordinary allozyme structure of the Lophuromys populations suggest that these populations represent remnants or direct descendants of relic local populations.     

The mycorrhizal status of vascular epiphytes in Bale Mountains National Park,Ethiopia

Roots of 28 species of epiphytic vascular plants were collected on tree trunks and branches at six afromontane forest sites between 1700 and 3300 m above sea level in Bale Mountains National Park, Ethiopia. Seven of the 28 epiphyte species were colonized by vesicular-arbuscular mycorrhizal fungi (VAM). Mycorrhizal colonization only occurred at two of the six sites examined, at 2900 m and 3300 m, but more than one type of VAM endophyte was present in each case. Three facultative epiphytic species were all highly colonized by VAM on the forest floor, whereas roots from epiphytic habitats were weakly colonized. No correlations were found between VAM colonization, fine root diameter and root hair length, but VAM colonization and root hair abundance were negatively correlated. The lack of VAM colonization of potential, epiphytic host species at the majority of the sites examined points to the dispersal of VAM propagules as the factor limiting mycorrhizal colonization of epiphytic habitats. It is suggested that root systems of hemiepiphytic tree species serve as corridors between forest floor and tree trunks through which VAM may spread via hyphal growth.     

Population status and structure of mountain nyala in the Bale Mountains National Park, Ethiopia

The study on the population status and structure of mountain nyala (Tragelaphus buxtoni) was carried out in the Bale Mountains National Park, Ethiopia during the wet and dry seasons of 2000/2001. Total counts were carried out in an area of 13.1 km². The count ranged between 682 and 732 individuals. Females comprised 62.9% while males 27.4%. The calf ratio was 9.7%. The group structure of the animals varied with season. Large herds were frequently observed during the wet season and smaller groups during the dry season. Group size changed seasonally. In both seasons, 7–12 individuals were the frequent group size formation. The maximum group (62) was observed during the wet season. The population trend of the animal from 1975 to 1990 indicated a recovery and increase. But between 1990 and 1995 the population showed a continuous and steep decline. However, between 1995 and 2000 the population trend showed a better condition when compared with the previous years.     

Demography and dynamics of mountain nyala Tragelaphus buxtoni in the Bale Mountains National Park,Ethiopia

We studied the population dynamics of endangered mountain nyala Tragelaphus buxtoni between 2003-2005 in the Bale Mountains National Park. Line-transect sampling and total count methods were used to gather data on demographics and movement patterns. The population's age-group composition was 58% adults, 25% sub-adults, 9% juveniles, 5% calves and 3% unidentified with a female-male sex ratio of 2:1. Population density was found to be significantly different between the two sub-populations (Dinsho Sanctuary a...     

Sex chromosomes at early meiosis in three wood mice species of the genus Apodemus (Rodentia, Muridae)

The prophase of the first meiotic division was studied in field mice of the species Apodemus (Sylvaemus) flavicollis, A. (S.) ponticus, and A. (S.) uralensis by light and electron microscopy. The karyotypes of the species were described on the base of electron microscopy of synaptonemal complexes in spermatocytes I. The axial elements of the sex chromosomes at early-middle pachytene can synapse along the major portion of the Y axis; at late pachytene-early diplotene, the synapsis region shrinks; and at diakinesis-metaphase I, X and Y chromosomes associate tail-to-tail in all species studied. The behavior of sex chromosomes in the synapsis in the species studied was quite uniform. The results are discussed in the context of earlier data on the behavior of sex chromosomes in various rodent species in meiosis prophase I and their banding.     

Small mammals of the Bale Mountains, Ethiopia

A sample of 535 small mammals, caught over a range of altitudes from 1500 to 4000 m in the Bale Mountains, on various expeditions from December 1971 to August 1986, enables the altitudinal zonation of the species to be delimited. The most abundant species, Lophuromys flavopunctatus, ranged from near the lower tree line at 1550 m, right up through the forested zones and onto the Afro-alpine moorland at 3900 m. The endemic Praomys albipes also ranged through the forest from 1550 to 3200 m, but was replaced in open habitats between 2400 and 3900 m by Stenocephalemys griseicauda and between 3000 and 4000 m by S. albocaudata, which was relatively more abundant than its congener at higher altitudes. Other moorland species, including Crocidura fumosa, Otomys typus, Lophuromys melanonyx and Arvicanthis blicki were also commonest at 3800–4000 m, but, like the Stenocephalemys spp., penetrated to lower altitudes in open habitats. Mus mahomet was confined to lower altitudes (1510–3000 m) and open habitats, apparently replaced by Mus triton, not previously recorded from Ethiopia, in forested habitats at middle altitudes (1950–2400 m).     

Molecular phylogeny and distribution of three Apodemus species (Muridae, Rodentia) in Serbia

Phylogenetic relationships among three species of the genus Apodemus ( A. flavicollis, A. sylvaticus and A. agrarius ) from seven different localities in Serbia were estimated using arbitrarily primed PCR (AP-PCR) profiling, which allowed clear distinction between the sibling species A. flavicollis and A. sylvaticus . Eight oligonucleotide primers out of the 22 screened, gained a total of 397 amplified bands. The average pairwise genetic distances within Apodemus species ranged from 0.51 between A. flavicollis and A. sylvaticus , to 0.74 between A. sylvaticus and A. agrarius. The large genetic distances obtained among populations of A. flavicollis (0.13) indicate that this part of the Balkan Peninsula was probably a refuge during the last glaciation. Furthermore, differences obtained between populations south and north from the river Danube suggest that this species survived the Last Glacial Maximum in at least two separate refuges. Although our data for molecular markers are from a limited number of localities, extended analyses of C-band distribution on chromosomes from previously studied localities south of the rivers Danube and Sava, indicate that distribution of A. sylvaticus is limited to northern Serbia. Therefore, it is possible that this part of the Balkan Peninsula was not a refuge for this species during the last glaciation.     

Isozyme and allozyme markers distinguishing two morphologically similar, medically important Mastomys species (Rodentia: Muridae)

Background  

Two common southern African mice species, Mastomys coucha and M. natalensis, are widely distributed throughout the subregion and overlap in many areas. They also share a high degree of morphological similarity, making them impossible to distinguish in the field at present. These multimammate mice are documented carriers of serious disease vectors causing Lassa fever, plague and encephalomyocarditis, which coupled to their cohabitation with humans in many areas, could pose a significant health risk. A preliminary study reported the presence of isozyme markers at three loci (GPI-2, PT-2, -3) in one population each of M. coucha and M. natalensis. Two additional populations (from the Vaal Dam and Richards Bay) were sampled to determine the reliability of these markers, and to seek additional genetic markers.     

High-Altitude Rock Shelters and Settlements in an African Alpine Ecosystem: The Bale Mountains National Park,Ethiopia

This first survey of rock shelters and settlements in the Bale Mountains in Ethiopia is a baseline assessment for further research into the settlement history of Africa’s largest alpine highlands. Extensive GPS-based mapping and interviews resulted in two detailed maps, a catalogue of profiles, and complete photographic documentation. In total, 331 rock shelters (four permanently inhabited, 51 seasonally inhabited, and 276 currently uninhabited) and 870 settlements (207 permanently inhabited, 449 seasonally inhabited, 214 uninhabited) were recorded together with information about the activities and livelihoods of the inhabitants of the current settlements. This 2015 study was part of the Ethiopian-European research project “The mountain exile hypothesis – how humans benefited from and re-shaped African high-altitude ecosystems during Quaternary climate changes” (DFG FOR 2358). It was designed to support future management plans in this internationally important conservation area that has recently faced increasing land-use pressure and the threat of degradation.     

Chromosomal variability of the field mouse Apodemus agarius (Rodentia, Muridae)

Chromosome sets of 114 Apodemus agrarius mice from 29 localities in Moldova, Ukraine, Siberia, and Far East were studied by means of G-, C-, and NOR-banding. In all populations studied, the Y chromosome was shown to be a medium-size acrocentric chromosome consisting of heterochromatin. Chromosome polymorphism observed in populations from Primorskii krai concerned (1) the morphology of the first two autosome pairs (variants A/A, A/ST, and ST/ST), (2) the number of metacentric chromosomes (from 6 to 8), and (3) heterochromatin localization in the pericentromeric regions of two metacentric chromosome pairs. A karyotype with an additional heterochromatic microchromosome found in all the metaphases studied was described in one mouse from a locality of western Primorye that has not been studied previously. In the karyotype of 15 mice from four populations of Primorye, the pool of nucleolus organizer regions is distributed over three autosome pairs rather than over four, as is the case A. agrarius from Europe. Based on the analysis of literature sources and our own data, the problem of chromosome polymorphism in the field mouse is discussed.     

Multivariate morphometries of the Ethiopian populations of harsh-furred rat (Lophuromys: Mammalia, Rodentia)

We investigated the geographic variation of eight Ethiopian populations of the rodent Lophuromys flavopunctatus and compared them to the Bale endemic species L. melanonyx. We used multivariate morphometrics and analysed independently skull and external body linear measurements, in an attempt to relate morphological variability to geography (latitude, longitude, altitude). There is a high morphological diversity in these Ethiopian populations, which form three distinct recognizable groups, with the Bale population being the most distinct. The results of analyses on the two character sets corroborate each other and indicate that the kind of variation is not 'ecological' but rather there is a phylogenetic cause, and relations at higher taxonomic level are suggested. There is a homogeneous group with five populations within which there is a recognizable pattern of clinal variation related to altitude, with a decrease in body size and a change in skull shape.     

Oligoryzomys flavescens (Rodentia, Muridae): gene flow among populations from central-eastern Argentina

In species acting as hosts of infectious agents, the extent of gene flow between populations is of particular interest because the expansion of different infectious diseases is usually related to the dispersal of the host. We have estimated levels of gene flow among populations of the sigmodontine rodent Oligoryzomys flavescens, in which high titers of antibodies have been detected for a Hantavirus in Argentina that produces a severe pulmonary syndrome. Enzyme polymorphism was studied by means of starch gel electrophoresis in 10 populations from the area where human cases of Hantavirus have occurred. Genetic differentiation between populations was calculated from F_ST values with the equation Nm = [(1/F_ST−1]/4. To assess the relative importance of current gene flow and historical associations between populations, the relationship of population pairwise log Nm and log geographic distance was examined. Low F_ST (mean = 0.038) and high Nm (15.27) values suggest high levels of gene flow among populations. The lack of an isolation by distance pattern would indicate that this species has recently colonized the area. The northernmost population, located on the margin of a great river, shows very high levels of gene flow with the downstream populations despite the large geographic distances. Passive transport of animals down the river by floating plants would promote unidirectional gene flow. This fact and the highest mean heterozygosity of that northernmost population suggest it is a center of dispersal within the species' range. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cytogenetic differentiation of Apodemus peninsulae populations (Rodentia, Muridae) in eastern Siberia

Population and cytogenetics studies of geographical karyotype changes in East Asiatic mice in East Siberia showed that each population has unique cytogenetic structure, owing to different variants of B-chromosomes system, including 1 to 18 B-chromosomes differing in morphology and size. For each population, we observed the prevalence of mice with a definite number and morphology of B-chromosomes, which is probably the result of homeostatic processes in the population. Local changes were revealed, due to increase in the number of dot-like B-chromosomes in the direction from the West to the East.     

Analysis of allozyme variability in three Plantago species and a comparison to morphological variability

Summary The level of electrophoretic variability in three Plantago species, P. major, P. coronopus, and P. lanceolata, was analyzed in relation to their breeding systems and compared with their morphological variability. From each species several populations were analyzed. The outcrossing P. lanceolata had the highest level of electrophoretic variability and the lowest population differentiation. The inbreeding P. major showed the opposite: a low level of electrophoretic variability and a high population differentiation. P. coronopus, with an intermediate breeding system, had an intermediate level of variability and differentiation. In comparing the species, it appeared that P. coronopus and P. major showed good concordance in the distribution of both kinds of variability, each having only a slightly higher morphological than electrophoretic differentiation between populations. P. lanceolata showed a higher morphological than electrophoretic differentiation between populations. A comparison of populations, within species, revealed good concordance of electrophoretic and morphological variability only within P. coronopus, while some populations of the other two species had relatively lower morphological variability compared with electrophoretic variability.Grassland Species Research Group Publication No. 182     

Cranial morphometric and fine scale genetic variability of two adjacentMastomys natalensis (Rodentia: Muridae) populations

The objective of this multidisciplinary project was to study the intra-specific morphometric and genetic variability between two adjacent populations ofMastomys natalensis Smith, 1834 living in different environments. The study of micro-evolutionary processes at work by using geometrical morphometrics allowed us to define two groups, characterized by different features of the skull shape. Using molecular microsatellites analysis, we showed that the two populations exchanged high gene flow and could be considered as a single panmictic unit. These results suggest that this widely-distributed species exhibits a local population-level differentiation in shape variation of skulls, probably due to different ecological situations. We speculate that the variability in the cranial characteristics (connected with the feeding ability) could reveal a local adaptation preferentially based on the food availability. We propose an explanation linking the shape differences to the fitness gain in the exploitation of resources available in the two environments. Since we suggest a potential differentiation process between populations, we believe that the two groups constitute even better models to understand the factors involved in the early stages of local adaptations.     

Epigenetic polymorphism in populations of Apodemus sylvaticus and Apodemus flavicollis (Rodentia, Muridae)

The main object of this study was to use discontinuous variation as a means of measuring divergence between populations of A. sylvaticus (L.) and A. flavicollis (Melchior) from Britain and Eurasia. Samples from 17 populations (671 skulls) were each classified for 20 discontinuous morphological variants. The investigation has shown that certain epigenetic variants have a characteristic incidence in populations of the two species and that the relative incidence of the variants could be used as an aid to specific separation. The calculation of degree of divergence between the populations has made it possible to suggest the order in which populations are related to each other.     

Bibliography of the genus Apodemus (Rodentia, Muridae)

A complete bibliography of the genus Apodemus for the period 1970–1980 is presented, with a selection of the more important papers from earlier years, and a few references for 1981. A coded index to species and subjects is provided. All titles have been translated into English.     

Assessment of three mitochondrial genes (16S, Cytb, CO1) for identifying species in the Praomyini tribe (Rodentia: Muridae)

The Praomyini tribe is one of the most diverse and abundant groups of Old World rodents. Several species are known to be involved in crop damage and in the epidemiology of several human and cattle diseases. Due to the existence of sibling species their identification is often problematic. Thus an easy, fast and accurate species identification tool is needed for non-systematicians to correctly identify Praomyini species. In this study we compare the usefulness of three genes (16S, Cytb, CO1) for identifying species of this tribe. A total of 426 specimens representing 40 species (sampled across their geographical range) were sequenced for the three genes. Nearly all of the species included in our study are monophyletic in the neighbour joining trees. The degree of intra-specific variability tends to be lower than the divergence between species, but no barcoding gap is detected. The success rate of the statistical methods of species identification is excellent (up to 99% or 100% for statistical supervised classification methods as the k-Nearest Neighbour or Random Forest). The 16S gene is 2.5 less variable than the Cytb and CO1 genes. As a result its discriminatory power is smaller. To sum up, our results suggest that using DNA markers for identifying species in the Praomyini tribe is a largely valid approach, and that the CO1 and Cytb genes are better DNA markers than the 16S gene. Our results confirm the usefulness of statistical methods such as the Random Forest and the 1-NN methods to assign a sequence to a species, even when the number of species is relatively large. Based on our NJ trees and the distribution of all intraspecific and interspecific pairwise nucleotide distances, we highlight the presence of several potentially new species within the Praomyini tribe that should be subject to corroboration assessments.