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1.
The genetic relationships of mantis shrimp Oratosquilla oratoria between the coastal waters of China and Japan were not well studied. To reveal the genetic differentiation and genetic structure among populations, we collected populations of mantis shrimp O. oratoria from the coastal waters of China and Japan to analyze the mtDNA control region variation. A total of 309 individuals of O. oratoria were collected from 13 localities (11 from China and 2 from Japan) and a segment of mitochondrial DNA control region was sequenced. Three hundred nine haplotypes were defined, yielding a very high haplotype diversity and nucleotide diversity. Two lineages of O. oratoria were revealed and displayed strong differences in the geographical distribution. In the coastal waters of China, the geographic distribution of the two lineages was completely separated by the Yangtze River estuary; however, the lineages showed geographic sympatry in two populations from Japan. Based on the lineage distribution, three groups were defined. There was no significant genetic differentiation among the populations within the three groups, indicating high gene flow within each group. Significant and negative values for Tajima D and Fu’s Fs tests, and mismatch distributions for two lineages indicated population expansion. The present result confirmed that the freshwater outflow from the Yangtze River formed a physical barrier and affected gene exchange. The different distribution patterns of the two lineages in coastal waters of China and Japan indicated that the larvae of O. oratoria were transferred from China to the coastal waters of Japan with a one-way gene flow.  相似文献   

2.
The elucidation of species diversity and connectivity is essential for conserving coral reef communities and for understanding the characteristics of coral populations. To assess the species diversity, intraspecific genetic diversity, and genetic differentiation among populations of the brooding coral Seriatopora spp., we conducted phylogenetic and population genetic analyses using a mitochondrial DNA control region and microsatellites at ten sites in the Ryukyu Archipelago, Japan. At least three genetic lineages of Seriatopora (Seriatopora-A, -B, and -C) were detected in our specimens. We collected colonies morphologically similar to Seriatopora hystrix, but these may have included multiple, genetically distinct species. Although sexual reproduction maintains the populations of all the genetic lineages, Seriatopora-A and Seriatopora-C had lower genetic diversity than Seriatopora-B. We detected significant genetic differentiation in Seriatopora-B among the three populations as follows: pairwise F ST = 0.064–0.116 (all P = 0.001), pairwise G′′ST = 0.107–0.209 (all P = 0.001). Additionally, only one migrant from an unsampled population was genetically identified within Seriatopora-B. Because the peak of the settlement of Seriatopora larvae is within 1 d and almost all larvae are settled within 5 d of spawning, our observations may be related to low dispersal ability. Populations of Seriatopora in the Ryukyu Archipelago will probably not recover unless there is substantial new recruitment from distant populations.  相似文献   

3.
North African odonates are facing conservation challenges, not only by increased degradation and loss of habitat, but also by having poorly understood taxonomy. Coenagrion puella is a widely distributed damselfly but there is debate about the taxonomic status of North African populations, where the species is very rare. We evaluate the genetic distinctiveness of North African C. puella using mitochondrial and nuclear genetic markers. We found a clear genetic differentiation between North African and European populations (3.4 % mtDNA) and a lack of shared haplotypes between individuals from the two continents. These results suggest that the damselfly C. puella comprises two genetically distinct phylogenetic lineages: one in Europe and one in North Africa, and re-invigorate the debate on the validity of the North African endemic C. puella kocheri. We propose that these two lineages of C. puella should be managed as distinct molecular operational taxonomic units. More generally, this study reinforces the important role of North Africa as centre of speciation and differentiation for odonates, and highlights the relevance of incorporating genetic data to understand the evolutionary history and taxonomy for effective biodiversity conservation.  相似文献   

4.
Sequence variation of the mitochondrial DNA control region was studied in Manchurian pheasants (Phasianus colchicus pallasi Rotshild, 1903) representing three geographic populations from the southern part of the Russian Far East. Extremely low population genetic differentiation (F ST = 0.0003) pointed to a very high gene exchange between the populations. Combination of such characters as high haplotype diversity (0.884 to 0.913), low nucleotide diversity (0.0016 to 0.0022), low R2 values (0.1235 to 0.1337), certain patterns of pairwise-difference distributions, and the absence of phylogenetic structure suggested that the phylogenetic history of Ph. c. pallasi included passing through a bottleneck with further expansion in the postglacial period. According to the data obtained, it was suggested that differentiation between the mitochondrial lineages started approximately 100000 years ago.  相似文献   

5.
To optimize conservation efforts, it is necessary to determine the risk of extinction by collecting reliable population information for a given species. We developed eight novel, polymorphic microsatellite markers and used these markers in conjunction with twelve existing markers to measure genetic diversity of South Korean populations of leopard cat (Prionailurus bengalensis), a species for which population size and habitat area data are unknown in the country, to assess its conservation status. The average number of alleles and the observed heterozygosity of the species were 3.8 and 0.41, respectively, and microsatellite diversity was lower than the average genetic diversity of 57 populations of 12 other felid species, and lower than that of other mammal populations occurring in South Korea, including the raccoon dog (Nyctereutes procyonoides), water deer (Hydropotes inermis), and endangered long-tailed goral (Naemorhedus caudatus). Furthermore, analysis of genetic structure in the national leopard cat population showed no clear genetic differentiation, suggesting that it is not necessary to divide the South Korean leopard cat population into multiple management units for the purposes of conservation. These results indicate that the genetic diversity of the leopard cat in South Korea is unexpectedly low, and that the risk of local extinction is, as a result, substantial. Thus, it is necessary to begin appropriate conservation efforts at a national level to conserve the leopard cat population in South Korea.  相似文献   

6.
Molecular genetic analysis of some ecological forms of whitefish belonging to the Coregonus lavaretus (L.) complex from different water bodies of Siberia revealed a high degree of differentiation between them. On the basis of the analysis of the mitochondrial DNA protein-coding ND1 gene, it was demonstrated that the previously described ecological forms of C. anaulorum, Yenisei River whitefish, or Issatschenko’s whitefish (C. fluviatilis), and cisco-like whitefish from Lake Baunt were good biological species. Moreover, each ecological form was represented by a number of phylogenetic lineages, one of which was species-specific. The remaining lineages were characterized by the mitochondrial DNA of another whitefish species, usually, the most common in each geographic region. The results of genetic analysis demonstrated that the formation of modern ecological forms of Siberian pidschian-like whitefish was accompanied by natural introgressive hybridization. It is suggested that most of the modern pidschian-like whitefish species originated as a result of reticulate evolution.  相似文献   

7.
8.
Cycas debaoensis is a critically endangered cycad species endemic to China. This species is found on two kinds of habitats according to the edaphic differences, sand and karst. A previous chloroplast DNA (cpDNA) study indicated that C. debaoensis had low genetic variation within populations and high genetic differentiation among populations. Because maternally inherited cpDNA does not fully characterize genetic structure of the species, we screened seven low-copy nuclear genes and 17 nuclear microsatellite loci to detect the nuclear genetic diversity, differentiation, and the population structure of C. debaoensis. The nuclear genes revealed higher level of genetic diversity. There were both the same and region-specific haplotypes or alleles between the karst and sand regions. Nuclear gene flow among all the populations was much greater than that of cpDNA, which indicated that pollen-mediated gene flow was much greater than seed-mediated gene flow. This promoted low nuclear genetic differentiation among populations of C. debaoensis. The study suggests that both genetic and anthropogenic disturbances have resulted in the critically endangered status of C. debaoensis.  相似文献   

9.
Geometric morphometrics and molecular methods are effective tools to study the variability of stingless bee populations and species that merit protection given their worldwide decline. Based on previous evidence of cryptic lineages within the Scaptotrigona genus, we tested the existence of multiple evolutionary lineages within the species S. mexicana and we investigated the status of S. pectoralis. By analyzing their population structure, we found differences between the Pacific and Atlantic populations of each of these species, although geometric morphometrics of the wing only confirmed these results in S. mexicana. There was a tendency towards enhanced genetic differentiation over larger distances in the Atlantic populations of both species but not in the Pacific populations. These results revealed a pattern of differentiation among evolutionary units and a specific distribution of genetic diversity within these Scaptotrigona species in Mesoamerica, suggesting the need for future taxonomic revisions, as well as activities aimed at management and conservation.  相似文献   

10.
The gastropod Hexaplex trunculus is widely distributed in a relatively large range of habitats, but has no dispersal stage. We investigated its genetic structure across its distribution range, from Mediterranean Sea to adjacent Atlantic coasts, by sequencing mitochondrial DNA portions of the NADH dehydrogenase gene ND2 (420 pb) and the internal transcribed spacer ITS2 (450 pb). Our results suggested a significant genetic variability of ND2 (π = 0.009 and Hd = 0.629) and low variability of the ITS2 sequences. A strong phylogeographic break, separated the Aegean populations from those of Western/Eastern Mediterranean and the Atlantic ones, was founded. The tow lineages may have been separated by vicariance events due to the Peloponnese break that separates the Aegean populations from other populations and was maintained until now by the quasi-circular anticyclonic front associated to the straits of Cretan Arc of the Peloponnesian Peninsula. Tunisian coasts appear particularly diverse since the two divergent lineages co-occured. These results may have management consequences since H. trunculus is a high commercial value harvested species.  相似文献   

11.
Melampyrum sylvaticum is an endangered annual hemiparasitic plant that is found in only 19 small and isolated populations in the United Kingdom (UK). To evaluate the genetic consequences of this patchy distribution we compared levels of diversity, inbreeding and differentiation from ten populations from the UK with eight relatively large populations from Sweden and Norway where the species is more continuously distributed. We demonstrate that in both the UK and Scandinavia, the species is highly inbreeding (global F IS = 0.899). Levels of population differentiation were high (FST = 0.892) and significantly higher amongst UK populations (FST = 0.949) than Scandinavian populations (FST = 0.762; P < 0.01). The isolated populations in the UK have, on average, lower genetic diversity (allelic richness, proportion of loci that are polymorphic, gene diversity) than Scandinavian populations, and this diversity difference is associated with the smaller census size and population area of UK populations. From a conservation perspective, the naturally inbreeding nature of the species may buffer the species against immediate effects of inbreeding depression, but the markedly lower levels of genetic diversity in UK populations may represent a genetic constraint to evolutionary change. In addition, the high levels of population differentiation suggest that gene flow among populations will not be effective at replenishing lost variation. We thus recommend supporting in situ conservation management with ex situ populations and human-mediated seed dispersal among selected populations in the UK.  相似文献   

12.
Redside dace Clinostomus elongatus (Teleostei: Cyprinidae) is a species of conservation concern that is declining throughout its range as a result of habitat fragmentation, degradation and loss. We characterized the genetic structure and diversity of redside dace populations across the species range using mitochondrial and microsatellite data to inform conservation efforts and assess how historical and recent events have shaped genetic structure and diversity within and among populations. Phylogeographic structure among 28 redside dace populations throughout southern Ontario (Canada) and the United States was assessed by sequence analysis of the mitochondrial cytochrome b and ATPase 6 and 8 genes. Populations were also genotyped using ten microsatellite loci to examine genetic diversity within and among populations as well as contemporary spatial structuring. Mitochondrial DNA sequence data revealed three geographically distinct lineages, which were highly concordant with groupings identified by microsatellite analysis. The combined genetic data refute published glacial refugia hypotheses of a single Mississippian refugium or of two lineages associated with Mississippian and Atlantic refugia. Secondary contact between the two eastern groups was documented in the Allegheny River drainage and tributaries to Lake Ontario. With the exception of several allopatric populations within the Allegheny watershed, high genetic structuring among populations suggests their isolation, indicating that recovery efforts should be population-based.  相似文献   

13.
The aim of this study was to investigate whether Pleistocene climatic instability influenced the phylogeographic structure and historical demography of an endemic Atlantic Forest (AF) orchid bee, Euglossa iopoecila Dressler, which shows two main patterns of integument colors over of its geographical distribution. We based our analysis on the concatenated sequence of four mtDNA segments belonging to genes 16S (357 bp), Cytb (651 bp) and COI (1206 bp), totaling 2234 bp. Samples of E. iopoecila populations were collected in 14 AF remnants along its geographic distribution. Median-Joining haplotype networks, SAMOVA and BAPS results indicated three lineages (southern, central and northern clusters) for E. iopoecila, with two important phylogeographic ruptures. We found higher genetic diversity among samples collected in the central region of the AF, which coincides with predicted areas of climatic stability, according to recent AF stability–extinction model. The demographic analysis suggests that only the southern cluster had undergone recent population expansion, which probably started after the last glacial maximum (LGM). Our data suggest that the differentiation observed in the three mitochondrial lineages of E. iopoecila is the result of past disconnections and multiple extinction/recolonization events involving climate fluctuations. In terms of conservation, we would emphasize the importance of considering: (1) the region of the central clade as the location of the highest genetic diversity of mtDNA of E. iopoecila populations; (2) the philopatric behavior of females that tends to restrict mtDNA gene flow in particular, with direct implications for the conservation of the total genetic diversity in euglossine populations.  相似文献   

14.
The present-day contact zone between the Beringian and Arctic phylogenetic lineages of charrs of the genus Salvelinus in the Northwest Pacific is documented. A comparative analysis of the genetic differentiation and divergence indices for allopatric and sympatric populations of charrs and phylogenetic and genealogical analyses of the mtDNA haplotypes indicate that Lake Achchen and the Lake Pekulineiskoe are the zones of secondary contact between S. m. malma and S. taranetzi; Lake Nachikinskoe, between S. m. malma and Salvelinus sp. 4; and Lake Dal’nee, between S. m. malma and S. krogiusae. The level of divergence between phylogenetic groups of haplotypes considerably exceeds the range of intraspecific variability of S. m. malma and could not have been achieved after colonization of the lakes in conditions of sympathy. The obtained data suggest that the territory of Kamchatka was colonized by the common ancestor of the Arctic phylogroup of Taranetz charr.  相似文献   

15.
The red clover casebearer, Coleophora deauratella, is an invasive pest of red clover grown for seed in North America. In 2006, an outbreak in Alberta, Canada was discovered that resulted in significant seed losses, while further invasion threatens the world’s largest red clover forage seed production region in Oregon, USA. Prior to the recent outbreak, C. deauratella was thought to be restricted to eastern North America in its invasive range. We sequenced a 615-bp fragment of the mitochondrial cytochrome c oxidase subunit 1 gene, and developed three microsatellite markers to assess the genetic diversity and population structure of C. deauratella in North America and its native range in Europe. We observed signatures of a founder effect in North American populations and a further loss of genetic diversity within Alberta populations. Most genetic differentiation was found between continents, with no evidence of isolation-by-distance within each continent. From the limited number of European populations sampled, a single introduction from Switzerland is the most probable source of North American populations based on similar mitochondrial diversity and lack of population differentiation. Within North America, based on increased genetic diversity compared to the rest of the continent, the first North American record from Ithaca, NY, and the first documented outbreak in southern Ontario in 1989, the initial C. deauratella invasion most likely occurred in southern Ontario, Canada or adjacent states in the USA, followed by transport throughout the continent. This study provides insight into the phylogeographic history of C. deauratella in North America and Europe and may help to identify a regional source of future classical biological control agents.  相似文献   

16.
Rosa praelucens is a critically endangered decaploid alpine rose with an extremely narrow geographic distribution in Northwestern Yunnan, China. We sampled almost all the extant individuals (527 individuals in 31 natural locations and 56 individuals preserved in three local living collections) to assess the genetic variation and to probe the genetic connectivity among the individuals and populations based on three cpDNA intergenic spacers and six fluorescent amplified fragment length polymorphism (AFLP) markers. The morphological traits from seven populations were also measured. R. praelucens exhibited high levels of morphological variation, genetic diversity, and differentiation. The extant individuals were clustered into eight groups in neighbor-net networks, and subsequent Bayesian analysis assigned them into three larger gene pools, both in accordance with their morphological traits, especially flower color. The living collections embraced two private cpDNA haplotypes and included three out of the species’ total eight AFLP genotypes. Rhizome clonal growth, decaploid, and mixed breeding system may largely contribute to high genetic diversity and differentiation in R. praelucens. We concluded that the endangered status of R. praelucens may mainly be due to habitat fragmentation and loss and inherent reproductive difficulties, rather than low genetic diversity. The populations contributing higher cpDNA genetic diversity, representing more AFLP genotypes, and encompassing private cpDNA haplotypes should be given conservation priority by creating plant-micro reserves. The living collections should also be targeted for further ex situ conservation, population recovery, and reintroduction of R. praelucens plants.  相似文献   

17.

Background

Species delineation is particularly challenging in taxa with substantial intra-specific variation. In systematic studies of fishes, meristics and linear measurements that describe shape are often used to delineate species. Yet, little is known about the taxonomic value of these two types of morphological characteristics. Here, we used Tropheus (Teleostei, Cichlidae) from the southern subbasin of Lake Tanganyika to test which of these types of characters best matched genetic lineages that could represent species in this group of stenotypic rock-dwelling cichlids. We further investigated intra-population variation in morphology. By linking this to a proxy of a population’s age, we could assess the evolutionary stability of different kinds of morphological markers.

Results

Morphological data was collected from 570 specimens originating from 86 localities. An AFLP approach revealed the presence of five lineages in the southern subbasin: T. moorii, T. brichardi, T. sp. ‘maculatus’, T. sp. ‘Mpimbwe’ and T. sp. ‘red’, which we consider to represent distinct species. Although both types of morphological data supported this classification, a comparison of PST-values that describe inter-population morphological differentiation, revealed a better correspondence between the taxon delineation based on AFLP data and the patterns revealed by an analysis of meristics than between the AFLP-based taxon delineation and the patterns revealed by an analysis of shape. However, classifying southern populations of Tropheus was inherently difficult as they contained a large amount of clinal variation, both in genetic and in morphological data, and both within and among species. A scenario is put forward to explain the current-day distribution of the species and colour varieties and the observed clinal variation across the subbasin’s shoreline. Additionally, we observed that variation in shape was larger in populations from shallow shores whereas populations from steep shores were more variable in meristics. This difference is explained in terms of the different timescales at which small and large scale lake level fluctuations affected populations of littoral cichlids at steep and shallow shores.

Conclusions

Our results showed meristics to be more evolutionary stable, and of higher taxonomic value for species delimitation in Tropheus, than linear measurements that describe shape. These results should be taken into account when interpreting morphological differences between populations of highly stenotypic species, such as littoral cichlids from the Great East African Lakes.
  相似文献   

18.
The tropical snowflake octocoral Carijoa riisei, which is thought to be native to the Indo-Pacific biogeographical region, has been increasingly reported from the Colombian Tropical Eastern Pacific (TEP) over the past two decades. Massive mortalities of native octocorals, particularly in Pacifigorgia spp. and Muricea spp., were observed due to C. riisei overgrowth. However, the area of origin of TEP C. riisei remains unknown and its potential invasive status has not been addressed yet. We evaluated geographical scenarios for the colonization of the Colombian TEP by conducting phylogeographical analyses based on nuclear and mitochondrial sequences of 306 individual specimens from across the species’ (native/non-native) range and applying hypothesis-specific operational criteria. Additionally, we assessed whether C. riisei has to be considered an invasive species based on the previously proposed ‘unified framework for biological invasions’. Our results showed relatively high genetic differentiation between Colombian TEP populations, on the one side, and Indo-Pacific and Hawaiian populations, on the other side. In contrast, we could not identify genetic differentiation and significant isolation by distance (IBD) between Colombian TEP and Tropical Atlantic populations. C. riisei might have been introduced from the Atlantic into the Colombian TEP, possibly via the Panama Canal. Based on the criteria of the ‘unified framework for biological invasions’, we also conclude that this octocoral constitutes an invasive species. Our study may serve as a basis for establishing strategies to protect native species from one of the very few invasive coral species worldwide.  相似文献   

19.
The uplift of mountains and climatic oscillations are important for understanding of the demographic history and genetic structure of species. We investigated the biogeographic history of the boreal tree species Ulmus lamellosa (Ulmaceae) in China, by using a combined phylogeographic and paleodistribution modeling approach. In this study, 14 populations of endangered U. lamellosa were analyzed by using chloroplast DNA (cpDNA) sequences. A high level of genetic differentiation (Φ ST = 86.22%) among populations with a significant phylogeographic pattern (N ST > G ST, P < 0.05) was found in U. lamellosa. Ten haplotypes were detected by combining chloroplast DNA data, and haplotype 3 (H3) was found to be common and widespread. The intraspecific divergence of all U. lamellosa cpDNA haplotypes (9.27 Ma; 95% HPD 5.17–13.33 Ma) most probably began in the late Miocene. The pairwise difference among haplotypes and neutrality tests (Tajima’s D and Fu’s Fs statistic) indicated that populations of U. lamellosa, except group I, have not experienced recent sudden expansions. Multiple refuge areas were identified across the entire distribution ranges of U. lamellosa. The low level of gene flow (Nm = 0.14) among populations may have resulted from isolation resulting from distance and complex topography during climatic oscillations; this isolation was probably the major process that shaped the present distribution of haplotypes. These results support the hypothesis that U. lamellosa persisted in situ during glaciations and occupied multiple localized glacial refugia, contrary to the hypotheses of large-scale range contraction and long-distance southward migration.  相似文献   

20.
Subspecies were traditionally defined by identifying gaps between phenotypes across the geographic range of a species, and may represent important units in the development of conservation strategies focused on preserving genetic diversity. Previous taxonomic research proposed that phenotypic variation between scattered Indri indri populations warranted the naming of two distinct subspecies, I. i. indri and I. i. variegatus. We tested these subspecific designations using mitochondrial sequence data generated from the control region or D-loop (569 bp) and a large section (2362 bp) of multiple genes and tRNAs known as Pastorini’s fragment and nuclear microsatellite markers. This study used 114 samples of I. indri from 12 rainforest sites in eastern Madagascar, encompassing the entire range of the species. These genetic samples represent multiple populations from low- and high-elevation forests from both putative subspecies. Molecular analyses of the mitochondrial sequence data did not support the two proposed subspecies. Furthermore, the microsatellite analyses showed no significant differences across the range beyond population level differentiation. This study demonstrates the utility of incorporating multiple lines of evidence in addition to phenotypic traits to define species or subspecies.  相似文献   

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