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1.
To evaluate the intraspecific evolutionary history and local differentiation of the Japanese water shrewChimarrogale platycephala (Temminck, 1842), we an a lyzed the mitochondrial cytochromeb (Cytb) sequence divergence for samples from 55 localities in the Japanese is lands of Honshu and Kyushu. According to phylogenetic trees based on theCytb data, there were fourCytb haplotype lineages, which showed rough affinities with geographic areas, namely, Eastern/Central Honshu, the Kinki District of Western Honshu, the Chugoku District of Western Honshu, and Kyushu. However, in the alpine areas of the boundary between the Kinki and Chugoku Districts, complicated distribution patterns of theCytb haplotypes were revealed. Considering the present data and geological history in the Quaternary, we hypothesized the following evolutionary scenario. First, differ entiation and division into four primary ancestral geographic colonies of the shrews occurred in hypothetical refugia in the mid — late Pleistocene. Subsequently, rapid expansion occurred and caused the complicated distribution patterns of theCytb haplotypes in the boundary areas owing to the complex topography during the late stage of the Quaternary.  相似文献   

2.
Using starch gel electrophoresis, geographical enzyme variation was surveyed in 46 populations of the Japanese salamander Hynobius nebulosus , which occurs widely in western Japan. This species exhibits substantial local genetic differentiation and is more diverse in inland regions than on small islands. In several different analyses, two groups of populations, one from Kyushu Island to the westernmost part of Chugoku district, Honshu (western group), and another from Shikoku through Kinki to Chubu district, Honshu (eastern group), were consistently recognized. Most of the remaining populations were placed in two less clearly-defined groups: the montane group from the Chugoku Mountains and the Chugoku group from the coastal regions of Chugoku district. The divergence patterns of H. nebulosus are thought to be related to the geological history of its range. The populations near the boundary of the western group were found to share several alleles that were predominant on both sides of the boundary, indicating past secondary contact. Differentiation in the montane group did not follow the isolation by distance model, probably because several populations included were genetically mixed with lowland populations of the Chugoku group.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 311–330.  相似文献   

3.
The genetic resources of a particular species of flowering cherry, Cerasus jamasakura, have high conservation priority because of its cultural, ecological and economic value in Japan. Therefore, the genetic structures of 12 natural populations of C. jamasakura were assessed using ten nuclear SSR loci. The population differentiation was relatively low (F ST, 0.043), reflecting long-distance dispersal of seeds by animals and historical human activities. However, a neighbor-joining tree derived from the acquired data, spatial analysis of molecular variance and STRUCTURE analysis revealed that the populations could be divided into two groups: one located on Kyusyu Island and one on Honshu Island. Genetic diversity parameters such as allelic richness and gene diversity were significantly lower in the Kyushu group than the Honshu group. Furthermore, STRUCTURE analysis revealed that the two lineages were admixed in the western part of Honshu Island. Thus, although the phylogeographical structure of the species and hybridization dynamics among related species need to be evaluated in detail using several marker systems, the Kyusyu Island and Honshu Island populations should be considered as different conservation units, and the islands should be regarded as distinct seed transfer zones for C. jamasakura, especially when rapid assessments are required.  相似文献   

4.
Hynobius naevius, distributed on western Honshu, Shikoku, and Kyushu Islands of Japan, includes two genetically distinct groups (Groups A and B) that have never been delimited morphologically. Using specimens from the entire species range, we investigated the possibility of distinguishing these groups morphologically. Multivariate analyses of morphometric characters resulted in recognition of two groups that corresponded well to the two genetic groups. One (Group A) was characterized by larger body, compressed tail, shallower vomerine tooth series, bluish- or reddish-purple ground color, and pale-white lateral markings. In contrast, another (Group B) was characterized by smaller body, cylindrical tail, longer vomerine tooth series, reddish-brown ground color, and white lateral markings. Group A was composed of populations from the Chugoku District of Honshu and northern Kyushu, and could not be divided into subgroups, while Group B encompassed populations from the Chubu and Kinki Districts of Honshu, Shikoku and Kyushu, and was subdivided into three local subgroups that are geographically separated by marine straits. Morphometric differentiation in Group A is presumed to have been less affected by genetic factors than by other factors, such as ecological relationships with other, coexisting species. Differentiation in Group B is assumed to have been enhanced not only by genetic but also by climatological factors.  相似文献   

5.
To test the association between temperate forest dynamics and glacial refugia for arboreal small mammals, we studied the phylogeography of the Japanese giant flying squirrel ( Petaurista leucogenys ) using complete mitochondrial cytochrome b gene sequences (1140 bp). This squirrel is endemic to three of Japan's main islands: Honshu, Shikoku, and Kyushu. We examined 58 specimens of P. leucogenys collected from 40 localities in Japan. Additionally, two individuals with unknown sampling localities were included in phylogenetic analyses. There were 54 haplotypes of P. leucogenys. We found five major phylogroups (Northern, Central, South-eastern, South-western, and Southern). These phylogroups may have originated from glacial refugia during the Late Pleistocene. After the last glaciation, the Northern phylogroup, widely distributed in eastern Japan, could have extensively expanded northward from its refugia. By contrast, in western Japan, population expansion was restricted to western Japan. All members of four phylogroups existed in western Japan during glaciations. The complicated phylogeographical pattern of P. leucogenys populations originating from western Japan may have resulted from the long history.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 47–60.  相似文献   

6.
We employed DNA sequence variation at two mitochondrial (control region, COI) regions from 212 individuals of Galaxias platei (Pisces, Galaxiidae) collected throughout Patagonia (25 lakes/rivers) to examine how Andean orogeny and the climatic cycles throughout the Quaternary affected the genetic diversity and phylogeography of this species. Phylogenetic analyses revealed four deep genealogical lineages which likely represent the initial division of G. platei into eastern and western lineages by Andean uplift, followed by further subdivision of each lineage into separate glacial refugia by repeated Pleistocene glacial cycles. West of the Andes, refugia were likely restricted to the northern region of Patagonia with small relicts in the south, whereas eastern refugia appear to have been much larger and widespread, consisting of separate northern and southern regions that collectively spanned most of Argentinean Patagonia. The retreat of glacial ice following the last glacial maximum allowed re‐colonization of central Chile from nonlocal refugia from the north and east, representing a region of secondary contact between all four glacial lineages. Northwestern glacial relicts likely followed pro‐glacial lakes into central Chilean Patagonia, whereas catastrophic changes in drainage direction (Atlantic → Pacific) for several eastern palaeolakes were the likely avenues for invasions from the east. These mechanisms, combined with evidence for recent, rapid and widespread population growth could explain the extensive contemporary distribution of G. platei throughout Patagonia.  相似文献   

7.
Aim The aim of this study is to detect extant patterns of population genetic structure of Fraxinus mandshurica var. japonica in Japan, and to provide insights into the post‐glacial history of this species during the Holocene. Location Hokkaido and Honshu islands, Japan (including the Oshima and Shimokita peninsulas). Methods We examined nine polymorphic nuclear microsatellite loci to assess genetic variation within and among 15 populations across almost the entire range of the species in Japan. Extant patterns of geographical structure were analysed using Bayesian clustering, Monmonier’s algorithm, analysis of molecular variance, Mantel tests and principal coordinates analysis. Recent bottlenecks within populations and regional genetic variation were also assessed. Results Northern populations (Hokkaido Island and the Shimokita Peninsula) formed a single homogeneous deme, maintaining the highest level of allelic diversity on the Oshima Peninsula. By contrast, southern populations (Honshu Island) demonstrated strong substructure on both coasts. Specifically, populations on the Pacific side of Honshu exhibited significant bottlenecks and erosion of allelic diversity but preserved distinct subclusters diverging from widespread subclusters on the Japan Sea side of this island. Main conclusions Genetic evidence and life history traits suggest that F. mandshurica occupied cryptic northern refugia on the Oshima Peninsula during the Last Glacial Maximum, which is reflected in the species’ extant northern distribution. Strong geographical structure in southern populations, in agreement with fossil pollen records, suggests geographical isolation by mountain ranges running north–south along Honshu. Given that this tree species is cold‐adapted and found in riparian habitats, populations on the Pacific side of Honshu probably contracted into higher‐elevation swamps during warm post‐glacial periods, leading to a reduction of effective population sizes and rare allelic richness.  相似文献   

8.
Forests dominated by broad-leaved evergreen trees cover a narrow zone of the southern coast of Korea as well as warm-temperate and subtropical regions of Japan. However, little is known about their establishment history, especially in Korea. Endemic Quercus acuta grows in Korea and Japan. We evaluated its genetic diversity, population structure, and degree of lineage admixture in terms of its distribution history. Analyses utilized seven nuclear microsatellites that were genotyped from 330 individuals of 16 populations. Genetic diversity was highest for the Japanese Kyushu populations. The allelic diversity of populations was similar between Jeju Island and Kyushu, implying that they are putative refugia. Although the mean F ST value was very low, patterns for isolation-by-distance were strong and significant. Results from Bayesian clustering and Monmonier’s algorithm indicated that populations are roughly partitioned from west (Korea and Kyushu) to east (Japanese Honshu). Therefore, the two divisions within this species are demographically independent and may have arisen due to past fragmentation. In considering the mixed genetic structure between Korea and Kyushu populations, and the higher levels of genetic diversity in mainland Korea relative to Honshu, we hypothesized that this species has been able to survive within Jeju Island and Kyushu. Consequently, mainland Korea populations might have been shaped by range expansion that kept them well mixed from a continuous and large genetic resource.  相似文献   

9.
A survey of genetic variation of lotic breeding salamander Hynobius naevius by starch gel electrophoresis using 26 populations from southwestern Japan revealed the presence of two genetically distinct groups (GROUP-A and B) which overlap distributional ranges in some parts of Kyushu. Degree of genetic differentiation between the two groups was larger in Kyushu, including sympatric area, than in allopatric areas. We surmise that the two groups first differentiated allopatrically and overlapped their distributions secondarily. The first genetic differentiation is considered to have occurred in the Pliocene as a result of isolation between northern (GROUP-A) and southern (GROUP-B) ancestral populations by the formation of the Seto Inland Sea, largely separating the present distributions of the two groups. Genetic diversities within the GROUP-A seem to have become complicated by isolations, disappearances of local populations, and subsequent range expansion of distributions in Chugoku and northern half of Kyushu regions. Within the GROUP-B, diversities first formed by isolation by distance have been retained and accelerated secondarily by the formations of the Kii and Bungo straits. Sympatric populations of the two groups in northern half of Kyushu seem to have overlapped their ranges by niche segregation.  相似文献   

10.
Chromosome numbers were determined for 340 plants ofCarex conica from 83 populations in Japan. Six aneuploids, 2n=32, 33, 34, 36, 37 and 38, were found. Plants with even diploid chromosome numbers 2n=32, 34, and 36 were the most common and had different geographical distributions. Individuals with 2n=32 were from islands in the Seto Inland Sea and nearby coastal areas of the Chugoku District of Honshu; those with 2n=34 were from the Kanto, Chubu and Kinki Districts of Honshu; those with 2n=36 were from the mountainous areas of Chugoku, Shikoku and Kyushu Districts. Canonical discriminant analysis of 17 morphological characters demonstrated that the plants with 2n=32 were clearly distinct from those with 2n=34 or 36. All four aneuploids with even chromosome numbers showed normal bivalent pairing at meiotic metaphase I and probably represent cytogenetically stable cytodemes. Plants with 2n=33 had one heteromorphic trivalent and 15 bivalents, indicating a structural mutation. At mitotic metaphase I, one chromosome was markedly larger than the others, suggesting that the 2n=33 plants arose from 2n=34 plants by fusion of two chromsomes. The plant with 2n=37 was intermediate in morphology betweenCarex conica (2n=36) andC. morrowii (2n=38) and probably originated as an interspecific hybrid between these species.  相似文献   

11.
 The fluvial sculpin, Cottus nozawae, is a coldwater-adapted fish distributed in Hokkaido Island and the northeastern part of Honshu Island (Tohoku District), Japan. Mitochondrial DNA (mtDNA) control region sequencing was used to investigate the geographic distribution of genetic variation and phylogeography of C. nozawae. Most populations possessed unique haplotypes, few being shared across river systems. Phylogenetic analysis of the sequences of the mtDNA control region and adjacent regions of C. nozawae revealed three distinct phylogenetic groups that differed by 3.05% to 3.11%, corresponding to distinct geographic regions, Hokkaido Island, northern Tohoku District, and Yamagata Prefecture (southwestern Tohoku District), respectively. The divergence times of three groups were estimated to be about 1.5 million years ago by applying a general rate for mtDNA, suggesting that the divergence among them might have occurred in the early Pleistocene. Divergence among the haplotypes within the group from the northern Tohoku District was also high (1.84%), no haplotypes being shared by local populations in different river systems in this region. Local populations from a single river system in this region comprise a distinct lineage that differed from other river systems. Such genetically divergent population structures among the different regions and river systems are considered to have resulted mainly from long-term isolation and restricted gene flow among river systems, probably promoted by the fluvial benthic life history and low dispersal ability of this species. Received: April 12, 2001 / Revised: December 1, 2001 / Accepted: December 19, 2001  相似文献   

12.
13.
Aim We examine several hypotheses emerging from biogeographical and fossil records regarding glacial refugia of a southern thermophilic plant species. Specifically, we investigated the glacial history and post‐glacial colonization of a forest understorey species, Trillium cuneatum. We focused on the following questions: (1) Did T. cuneatum survive the Last Glacial Maximum (LGM) in multiple refugia, and (if so) where were they located, and is the modern genetic structure congruent with the fossil record‐based reconstruction of refugia for mesic deciduous forests? (2) What are the post‐glacial colonization patterns in the present geographical range? Location South‐eastern North America. Methods We sampled 45 populations of T. cuneatum throughout its current range. We conducted phylogeographical analyses based on maternally inherited chloroplast DNA (cpDNA haplotypes) and used TCS software to reconstruct intraspecific phylogeny. Results We detected six cpDNA haplotypes, geographically highly structured into non‐overlapping areas. With one exception, none of the populations had mixed haplotype composition. TCS analysis resulted in two intraspecific cpDNA lineages, with one clade subdivided further by shallower diversification. Main conclusions Our investigation revealed that T. cuneatum survived the LGM in multiple refugia, belonging to two (western, eastern) genealogical lineages geographically structured across south‐eastern North America. The western clade is confined to the south‐western corner of T. cuneatum’s modern range along the Lower Mississippi Valley, where fossil records document a major refugium of mesic deciduous forest. For the eastern clade, modern patterns of cpDNA haplotype distribution suggest cryptic vicariance, in the form of forest contractions and subsequent expansions associated with Pleistocene glacial cycles, rather than simple southern survival and subsequent northward colonization. The north–south partitioning of cpDNA haplotypes was unexpected, suggesting that populations of this rather southern thermophilic species may have survived in more northern locations than initially expected based on LGM climate reconstruction, and that the Appalachian Mountains functioned as a barrier to the dispersal of propagules originating in more southern refugia. Furthermore, our results reveal south‐west to north‐east directionality in historical migration through the Valley and Ridge region of north‐west Georgia.  相似文献   

14.
To clarify the feeding habits and major food sources of sandy beach fishes, the gut contents of 55 fish species collected on a sandy beach at Fukiagehama, South-West Kyushu Island, Japan, were examined. Ontogenetic changes in food preference were recognized in nine species (Hypoatherina valenciennei, Lateolabrax japonicus, Trachurus japonicus, Sillago japonica, Sphyraena japonica, Paralichthys olivaceus, Heteromycteris japonica, Paraplagusia japonica, and Takifugu niphobles). A cluster analysis based on dietary overlaps showed that the sandy beach fish assemblage comprised six trophic groups (mysid, amphipod, zooplankton, juvenile fish, terrestrial insect, and mollusk feeders). Of these, the first three groups were the most abundantly represented, whereas the last two were represented by only a single species. These results indicated that epibenthic macrofauna, such as mysids and gammaridean amphipods, and zooplankton, were important food resources for the fish assemblage at the study site, but infaunal macrobenthos, such as polychaetes and bivalves, being relatively unimportant.  相似文献   

15.
Various hypotheses have been proposed about the Quaternary evolutionary history of plant species on the Qinghai–Tibet Plateau (QTP), yet only a handful of studies have considered both population genetics and ecological niche context. In this study, we proposed and compared climate refugia hypotheses based on the phylogeographic pattern of Anisodus tanguticus (three plastid DNA fragments and nuclear internal transcribed spacer regions from 32 populations) and present and past species distribution models (SDMs). We detected six plastid haplotypes in two well‐differentiated lineages. Although all haplotypes could be found in its western (sampling) area, only haplotypes from one lineage occurred in its eastern area. Meanwhile, most genetic variations existed between populations (FST = 0.822). The SDMs during the last glacial maximum and last interglacial periods showed range fragmentation in the western area and significant range contraction in the eastern area, respectively, in comparison with current potential distribution. This species may have undergone intraspecific divergence during the early Quaternary, which may have been caused by survival in different refugia during the earliest known glacial in the QTP, rather than geological isolation due to orogenesis events. Subsequently, climate oscillations during the Quaternary resulted in a dynamic distribution range for this species as well as the distribution pattern of its plastid haplotypes and nuclear genotypes. The interglacial periods may have had a greater effect on A. tanguticus than the glacial periods. Most importantly, neither genetic data nor SDM alone can fully reveal the climate refugia history of this species. We also discuss the conservation implications for this important Tibetan folk medicine plant in light of these findings and SDMs under future climate models. Together, our results underline the necessity to combine phylogeographic and SDM approaches in future investigations of the Quaternary evolutionary history of species in topographically complex areas, such as the QTP.  相似文献   

16.
Monitoring Sites 1000” – Japan's long‐term monitoring survey was established in 2003, based on the Japanese Government policy for the conservation of biodiversity. Ecological surveys have been conducted on various types of ecosystems at approximately 1000 sites in Japan for 15 years now and are planned to be carried out for 100 years. Since 2008, seaweed communities had been monitored at six sites, featuring the kelp (e.g. Saccharina and Ecklonia; Laminariales) and Sargassum (Fucales) communities in the subarctic and temperate regions of Japan. Annual surveys were carried out during the season when these canopy‐forming seaweeds are most abundant. A non‐destructive quadrat sampling method, with permanent quadrats placed along transects perpendicular to the shoreline, was used to determine species composition, coverage, and vertical distribution of seaweeds at these sites; while destructive sampling was done every 5 years to determine biomass. The occurrence of canopy‐forming species Saccharina japonica (var. japonica) and Ecklonia cava have appeared to be stable at the Muroran (southwestern part of Hokkaido Island) and Shimoda (Pacific coast of middle Honshu Island) sites, respectively; whereas the coverage of Ecklonia radicosa (= Eckloniopsis radicosa) at the Satsuma‐Nagashima site in southern part of Kyushu Island was highly variable until its sudden disappearance from the habitat in 2016. Thalli of E. radicosa lost most of their blades through browsing by herbivorous fish, and thus, this may be one of the causes of the decline. A shift in the community structure related to environmental changes had also been observed at some other sites. Pre‐ and post‐disaster data revealed the impact of the 2011 earthquake and tsunami disasters, including a shift in the vertical distribution of Ecklonia bicyclis (= Eisenia bicyclis) to shallower depths at the Shizugawa site in the Pacific coast of northern Honshu Island, due to seafloor subsidence.  相似文献   

17.
Reports of zoonotic infections with Onchocerca japonica (Nematoda: Filarioidea), which parasitizes the Japanese wild boar, Sus scrofa leucomystax, have recently increased in Japan. To predict the occurrence of infection in humans, it is necessary to determine the prevalence of O. japonica infection in the natural host animals. We investigated the presence of adult worms in the footpads, and of microfilariae in skin snips, taken from the host animals, between 2000 and 2018. Onchocerca japonica was found in 165 of 223 (74%) Japanese wild boars in Honshu and Kyushu. Among the nine regions studied, the highest prevalence of O. japonica infection was found in Oita, Kyushu, where 47 of 52 (90.4%) animals were infected. The ears were the predilection sites for O. japonica microfilariae. Adult worms of O. japonica were found more frequently in the hindlimbs than in the forelimbs of the host animals. Onchocerca takaokai was found in 14 of 52 (26.9%) Japanese wild boars in Oita. In Kakeroma Island among the Nansei Islands, both O. japonica and O. takaokai were isolated from the Ryukyu wild boar, S. s. riukiuanus. These observations could help predict future occurrences of human zoonotic onchocercosis in Japan.  相似文献   

18.
Sciadopitys verticillata is amongst the most relictual of all plants, being the last living member of an ancient conifer lineage, the Sciadopityaceae, and is distributed in small and disjunct populations in high rainfall regions of Japan. Although mega‐fossils indicate the persistence of the species within Japan through the Pleistocene glacial–interglacial cycles, how the species withstood the colder and drier climates of the glacials is not well known. The present study utilized phylogeography and palaeodistribution modelling to test whether the species survived within pollen‐based coastal temperate forest glacial refugia or within previously unidentified refugia close to its current range. Sixteen chloroplast haplotypes were found that displayed significant geographical structuring. Unexpectedly, northern populations in central Honshu most distant from coastal refugia had the highest chloroplast diversity and were differentiated from the south, a legacy of glacial populations possibly in inland river valleys close to its current northern range. By contrast, populations near putative coastal refugia in southern Japan, harboured the lower chloroplast diversity and were dominated by a single haplotype. Fragment size polymorphism at a highly variable and homoplasious mononucleotide repeat region in the trnT‐trnL intergenic spacer reinforced the contrasting patterns of diversity observed between northern and southern populations. The divergent histories of northern and southern populations revealed in the present study will inform the management of this globally significant conifer. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 108 , 263–277.  相似文献   

19.
Phylogenetic relationships among migratory locust (Locusta migratoria) populations in different climatic regions were analysed by sequencing four mitochondrial DNA regions, with special reference to the origin of Japanese populations. The populations are clearly separated into two clades: one consists of individuals from temperate and cold‐temperate areas of Japan and the Chinese continent, and the other comprises those from subtropical islands of Japan, Hainan Island in China, Timol Leste, Australia, Ethiopia, France, and some individuals from Tsushima Island and Honshu of Japan. The divergence time between the two clades is estimated to be 0.86–1.89 Mya. The phylogenetic analysis revealed that Japanese L. migratoria populations were composed of individuals of six different origins: (1) Hokkaido populations possibly from the Russian continent; (2) Honshu–Kyushu populations from the Chinese continent; (3) Southwest Island populations from Hainan Island or adjacent areas; (4) Ogasawara populations that might have originated from Micronesia; (5) part of the Tsushima population that originated from somewhere in the Asian tropics; and (6) a possible relict population of ancient southern haplotypes that exists in western areas of northern Honshu. The Tsugaru Straits and Tokara Straits have acted as effective geographical barriers, as in other organisms, isolating locust populations for a few thousand years. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 570–581.  相似文献   

20.
报道中国禾本科(Gramineae)小丽草属一新记录种——日本小丽草(Coelachne japonica Hack.),该种原记载特产于日本本州和九州,现在浙江省苍南县莒溪和泰顺县黄桥发现有该种分布。同时,还描述了该种形态特征与生境,提供活植物照片和凭证标本,重新修订浙江有分布的小丽草属植物。  相似文献   

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