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1.
Genetic improvement of coffee (Coffea arabica L.) is constrained by low genetic diversity and lack of genetic markers, suitable screening tools, information on the genetic make‐up of available gene pool and long generation time. In this context, use of DNA markers such as microsatellites that provide high genetic‐resolution becomes highly desirable. Here, we report the development of nine new microsatellite markers from partial genomic library of an elite variety of Coffea arabica. The developed microsatellites revealed robust cross‐species amplifications in 17 related species of coffee, and their Polymorphic Information Content varied from 0 to 0.6, 0 to 0.78 and 0.67 to 0.90 for the arabica, robusta genotypes and species representatives, respectively. The data thus suggest their potential use as genetic markers for assessment of germplasm diversity and linkage analysis of coffee.  相似文献   

2.
The extent of genetic diversity loss and former connectivity between fragmented populations are often unknown factors when studying endangered species. While genetic techniques are commonly applied in extant populations to assess temporal and spatial demographic changes, it is no substitute for directly measuring past diversity using ancient DNA (aDNA). We analysed both mitochondrial DNA (mtDNA) and nuclear microsatellite loci from 64 historical fossil and skin samples of the critically endangered Western Australian woylie (Bettongia penicillata ogilbyi), and compared them with 231 (= 152 for mtDNA) modern samples. In modern woylie populations 15 mitochondrial control region (CR) haplotypes were identified. Interestingly, mtDNA CR data from only 29 historical samples demonstrated 15 previously unknown haplotypes and detected an extinct divergent clade. Through modelling, we estimated the loss of CR mtDNA diversity to be between 46% and 91% and estimated this to have occurred in the past 2000–4000 years in association with a dramatic population decline. In addition, we obtained near‐complete 11‐loci microsatellite profiles from 21 historical samples. In agreement with the mtDNA data, a number of ‘new’ microsatellite alleles was only detected in the historical populations despite extensive modern sampling, indicating a nuclear genetic diversity loss >20%. Calculations of genetic diversity (heterozygosity and allelic rarefaction) showed that these were significantly higher in the past and that there was a high degree of gene flow across the woylie's historical range. These findings have an immediate impact on how the extant populations are managed and we recommend the implementation of an assisted migration programme to prevent further loss of genetic diversity. Our study demonstrates the value of integrating aDNA data into current‐day conservation strategies.  相似文献   

3.
Symbiodinium are a diverse group of unicellular dinoflagellates that are important nutritional symbionts of reef‐building corals. Symbiodinium putative species (‘types’) are commonly identified with genetic markers, mostly nuclear and chloroplast encoded ribosomal DNA regions. Population genetic analyses using microsatellite loci have provided insights into Symbiodinium biogeography, connectivity and phenotypic plasticity, but are complicated by: (i) a lack of consensus criteria used to delineate inter‐ vs. intragenomic variation within species; and (ii) the high density of Symbiodinium in host tissues, which results in single samples comprising thousands of individuals. To address this problem, Wham & LaJeunesse (2016) present a method for identifying cryptic Symbiodinium species from microsatellite data based on correlations between allele size distributions and nongeographic genetic structure. Multilocus genotypes that potentially do not recombine in sympatry are interpreted as secondary ‘species’ to be discarded from downstream population genetic analyses. However, Symbiodinium species delineations should ideally incorporate multiple physiological, ecological and molecular criteria. This is because recombination tests may be a poor indicator of species boundaries in Symbiodinium due to their predominantly asexual mode of reproduction. Furthermore, discontinuous microsatellite allele sizes in sympatry may be explained by secondary contact between previously isolated populations and by mutations that occur in a nonstepwise manner. Limitations of using microsatellites alone to delineate species are highlighted in earlier studies that demonstrate occasional bimodal distributions of allele sizes within Symbiodinium species and considerable allele size sharing among Symbiodinium species. We outline these issues and discuss the validity of reinterpretations of our previously published microsatellite data from Symbiodinium populations on the Great Barrier Reef (Howells et al. 2013).  相似文献   

4.
Prevention and early detection are well recognized as the best strategies for minimizing the risks posed by nonindigenous species (NIS) that have the potential to become marine pests. Central to this is the ability to rapidly and accurately identify the presence of NIS, often from complex environmental samples like biofouling and ballast water. Molecular tools have been increasingly applied to assist with the identification of NIS and can prove particularly useful for taxonomically difficult groups like ascidians. In this study, we have developed real‐time PCR assays suited to the specific identification of the ascidians Didemnum perlucidum and Didemnum vexillum. Despite being recognized as important global pests, this is the first time specific molecular detection methods have been developed that can support the early identification and detection of these species from a broad range of environmental sample types. These fast, robust and high‐throughput assays represent powerful tools for routine marine biosecurity surveillance, as detection and confirmation of the early presence of species could assist in the timely establishment of emergency responses and control strategies. This study applied the developed assays to confirm the ability to detect Didemnid eDNA in water samples. While previous work has focused on detection of marine larvae from water samples, the development of real‐time PCR assays specifically aimed at detecting eDNA of sessile invertebrate species in the marine environment represents a world first and a significant step forwards in applied marine biosecurity surveillance. Demonstrated success in the detection of D. perlucidum eDNA from water samples at sites where it could not be visually identified suggests value in incorporating such assays into biosecurity survey designs targeting Didemnid species.  相似文献   

5.
The common smooth‐hound (Mustelus mustelus ) is the topmost bio‐economically and recreationally important shark species in southern Africa, western Africa, and Mediterranean Sea. Here, we used the Illumina HiSeq? 2000 next‐generation sequencing (NGS ) technology to develop novel microsatellite markers for Mustelus mustelus . Two microsatellite multiplex panels were constructed from 11 polymorphic loci and characterized in two populations of Mustelus mustelus representative of its South African distribution. The markers were then tested for cross‐species utility in Galeorhinus galeus , Mustelus palumbes , and Triakis megalopterus , three other demersal coastal sharks also subjected to recreational and/or commercial fishery pressures in South Africa. We assessed genetic diversity (N A, A R, H O, H E, and PIC) and differentiation (F ST and D est) for each species and also examined the potential use of these markers in species assignment. In each of the four species, all 11 microsatellites were variable with up to a mean N A of 8, A R up to 7.5, H E and PIC as high as 0.842. We were able to reject genetic homogeneity for all species investigated here except for T . megalopterus . We found that the panel of the microsatellite markers developed in this study could discriminate between the study species, particularly for those that are morphologically very similar. Our study provides molecular tools to address ecological and evolutionary questions vital to the conservation and management of these locally and globally exploited shark species.  相似文献   

6.
There is a great need to develop efficient, noninvasive genetic sampling methods to study wild populations of multiple, co‐occurring, threatened felids. This is especially important for molecular scatology studies occurring in challenging tropical environments where DNA degrades quickly and the quality of faecal samples varies greatly. We optimized 14 polymorphic microsatellite loci for jaguars (Panthera onca), pumas (Puma concolor) and ocelots (Leopardus pardalis) and assessed their utility for cross‐species amplification. Additionally, we tested their reliability for species and individual identification using DNA from faeces of wild felids detected by a scat detector dog across Belize in Central America. All microsatellite loci were successfully amplified in the three target species, were polymorphic with average expected heterozygosities of HE = 0.60 ± 0.18 (SD) for jaguars, HE = 0.65 ± 0.21 (SD) for pumas and HE = 0.70 ± 0.13 (SD) for ocelots and had an overall PCR amplification success of 61%. We used this nuclear DNA primer set to successfully identify species and individuals from 49% of 1053 field‐collected scat samples. This set of optimized microsatellite multiplexes represents a powerful tool for future efforts to conduct noninvasive studies on multiple, wild Neotropical felids.  相似文献   

7.
Tamandua tetradactyla (Pilosa), the lesser anteater, is a medium‐size mammal from South America. Its wide distribution through different landscapes, solitary and nocturnal habits, and the difficulty to capture and contain specimens limit the amount of individuals and populations sampled during fieldworks. These features along with the lack of specific molecular markers for the lesser anteater might be the causes for paucity in population genetic studies for the species. Historical samples from museum specimens, such as skins, and non‐invasive samples, such as plucked hair, can be supplementary sources of DNA samples. However, the DNA quantity and quality of these samples may be limiting factors in molecular studies. In this study, we describe nine microsatellite loci for T. tetradactyla and test the amplification success, data reliability and estimate errors on both historical and non‐invasive sample sets. We tested nine polymorphic microsatellites and applied the quality index approach to evaluate the relative performance in genotype analysis of 138 historical samples (study skin) and 19 non‐invasive samples (plucked hair). The observed results show a much superior DNA quality of non‐invasive over historical samples and support the quality index analysis as a practical tool to exclude samples with doubtful performance in genetic studies. We also found a relationship between the age of non‐invasive samples and DNA quality, but lack of evidence of this pattern for historical samples.  相似文献   

8.
Keystone species in their native ranges, eucalypts, are ecologically and genetically very diverse, growing naturally along extensive latitudinal and altitudinal ranges and variable environments. Besides their ecological importance, eucalypts are also the most widely planted trees for sustainable forestry in the world. We report the development of a novel collection of 535 microsatellites for species of Eucalyptus, 494 designed from ESTs and 41 from genomic libraries. A selected subset of 223 was evaluated for individual identification, parentage testing, and ancestral information content in the two most extensively studied species, Eucalyptus grandis and Eucalyptus globulus. Microsatellites showed high transferability and overlapping allele size range, suggesting they have arisen still in their common ancestor and confirming the extensive genome conservation between these two species. A consensus linkage map with 437 microsatellites, the most comprehensive microsatellite‐only genetic map for Eucalyptus, was built by assembling segregation data from three mapping populations and anchored to the Eucalyptus genome. An overall colinearity between recombination‐based and physical positioning of 84% of the mapped microsatellites was observed, with some ordering discrepancies and sporadic locus duplications, consistent with the recently described whole genome duplication events in Eucalyptus. The linkage map covered 95.2% of the 605.8‐Mbp assembled genome sequence, placing one microsatellite every 1.55 Mbp on average, and an overall estimate of physical to recombination distance of 618 kbp/cM. The genetic parameters estimates together with linkage and physical position data for this large set of microsatellites should assist marker choice for genome‐wide population genetics and comparative mapping in Eucalyptus.  相似文献   

9.
Nearly 5 000 aphid species damage crops, either by sucking plant sap or as disease‐transmitting vectors. Microsatellites are used for understanding molecular diversity and eco‐geographical relationships among aphid species. Expressed sequence tag (EST)‐microsatellite motifs were identified through an in silico approach using inbuilt simple sequence repeat mining tools in aphid EST dataset. Microsatellite mining revealed one in every five aphid genes as containing a repeat motif, and out of 9 290 EST microsatellites mined from Aphis gossypii Glover and Acyrthosiphon pisum (Harris) (both Hemiptera: Aphididae), 80% were of A and/or T (AT, ATA, AAT, AATA, and ATTT) motifs, and the rest contained G and/or C motifs. All microsatellite sequences were annotated using BLAST. Primers for EST microsatellites were designed using the Primer 3.0 tool. 106 primer pairs of both dinucleotide repeats (DNRs) and trinucleotide repeats (TNRs), representing open reading frames (ORFs) and untranslated regions (UTRs), were synthesized to amplify 15 aphid species belonging to the subfamily Aphidinae, collected from diverse hosts. Four hundred forty‐five polymorphic alleles were amplified. Fifty TNR and 23 DNR microsatellites amplified across the species studied. Polymorphism information content values of microsatellites ranged from 0.23 to 0.91, amplifying 2–16 alleles. Genetic similarity indices were estimated using the ‘NTSYS‐pc’ software package. Unweighted pair group with arithmetic mean and principal component analysis resolved taxonomic relationships of the aphid species studied. The new aphid microsatellites developed will provide valuable information to researchers to study Indian aphid species diversity and genetic relationships.  相似文献   

10.
Selfish genetic elements (SGEs) are DNA sequences that are transmitted to viable offspring in greater than Mendelian frequencies. Medea SGEs occur naturally in some populations of red flour beetle (Tribolium castaneum) and are expected to increase in frequency within populations and spread among populations. The large‐scale U.S. distributions of Medea‐4 (M4) had been mapped based on samples from 1993 to 1995. We sampled beetles in 2011–2014 and show that the distribution of M4 in the United States is dynamic and has shifted southward. By using a genetic marker of Medea‐1 (M1), we found five unique geographic clusters with high and low M1 frequencies in a pattern not predicted by microsatellite‐based analysis of population structure. Our results indicate the absence of rigid barriers to Medea spread in the United States, so assessment of what factors have limited its current distribution requires further investigation. There is great interest in using synthetic SGEs, including synthetic Medea, to alter or suppress pest populations, but there is concern about unpredicted spread of these SGEs and potential for populations to become resistant to them. The finding of patchy distributions of Medea elements suggests that released synthetic SGEs cannot always be expected to spread uniformly, especially in target species with limited dispersal.  相似文献   

11.
Phytophthora nicotianae is a phytopathogenic oomycete with a wide host range and worldwide distribution. Rapid detection and diagnosis at the early stages of disease development are important for the effective control of P. nicotianae. In this study, we designed a simple and rapid loop‐mediated isothermal amplification (LAMP)‐based detection method for P. nicotianae. We tested three DNA extraction methods and selected the Kaneka Easy DNA Extraction Kit version 2, which is rapid and robust for LAMP‐based detection. The designed primers were tested using mycelial DNA from 35 species (81 isolates) of Phytophthora, 12 species (12 isolates) of Pythium, one isolate of Phytopythium and one isolate each from seven other soil‐borne pathogens. All of the 42 P. nicotianae isolates were detected by these primers, and no other isolates gave positive results. Three isolates were tested for the sensitivity of the reaction, and the lowest amounts of template DNA that could be detected were 10 fg for two isolates and 1 fg for the third. The target was detected within 25 min in all tested samples, including DNA extracted from both inoculated and naturally infected plants. In contrast, PCR assays with P. nicotianae‐specific primers failed or showed weakened detection in several samples. Thus, we found that the rapid DNA extraction and LAMP assay methods developed in this study can be used to detect P. nicotianae with high sensitivity, specificity and stability.  相似文献   

12.
Dispersal and migratory behavior are influential factors in determining how genetic diversity is distributed across the landscape. In migratory species, genetic structure can be promoted via several mechanisms including fidelity to distinct migratory routes. Particularly within North America, waterfowl management units have been delineated according to distinct longitudinal migratory flyways supported by banding data and other direct evidence. The greater white‐fronted goose (Anser albifrons) is a migratory waterfowl species with a largely circumpolar distribution consisting of up to six subspecies roughly corresponding to phenotypic variation. We examined the rangewide population genetic structure of greater white‐fronted geese using mtDNA control region sequence data and microsatellite loci from 23 locales across North America and Eurasia. We found significant differentiation in mtDNA between sampling locales with flyway delineation explaining a significant portion of the observed genetic variation (~12%). This is concordant with band recovery data which shows little interflyway or intercontinental movements. However, microsatellite loci revealed little genetic structure suggesting a panmictic population across most of the Arctic. As with many high‐latitude species, Beringia appears to have played a role in the diversification of this species. A common Beringian origin of North America and Asian populations and a recent divergence could at least partly explain the general lack of structure at nuclear markers. Further, our results do not provide strong support for the various taxonomic proposals for this species except for supporting the distinctness of two isolated breeding populations within Cook Inlet, Alaska (A. a. elgasi) and Greenland (A. a. flavirostris), consistent with their subspecies status.  相似文献   

13.
Although some taxa are increasing in number due to active management and predator control, the overall number of kiwi (Apteryx spp.) is declining. Kiwi are cryptic and rare, meaning current monitoring tools, such as call counts, radio telemetry, and surveys using detection dogs are labor‐intensive, yield small datasets, and require substantial resources or provide inaccurate estimates of population sizes. A noninvasive genetic approach could help the conservation effort. We optimized a panel of 23 genetic markers (22 autosomal microsatellite loci and an allosomal marker) to discriminate between all species of kiwi and major lineages within species, while simultaneously determining sex. Markers successfully amplified from both fecal and shed feather DNA samples collected in captivity. We found that DNA extraction was more efficient from shed feathers, but DNA quality was greater with feces, although this was sampling dependent. Our microsatellite panel was able to distinguish between contemporary kiwi populations and lineages and provided PI values in the range of 4.3 × 10?5 to 2.0 × 10?19, which in some cases were sufficient for individualization and mark–recapture studies. As such, we have tested a wide‐reaching, noninvasive molecular approach that will improve conservation management by providing better parameter estimates associated with population ecology and demographics such as abundance, growth rates, and genetic diversity.  相似文献   

14.
Recently, we reported the chloroplast genome‐wide association of oligonucleotide repeats, indels and nucleotide substitutions in aroid chloroplast genomes. We hypothesized that the distribution of oligonucleotide repeat sequences in a single representative genome can be used to identify mutational hotspots and loci suitable for population genetic, phylogenetic and phylogeographic studies. Using information on the location of oligonucleotide repeats in the chloroplast genome of taro (Colocasia esculenta), we designed 30 primer pairs to amplify and sequence polymorphic loci. The primers have been tested in a range of intra‐specific to intergeneric comparisons, including ten taro samples (Colocasia esculenta) from diverse geographical locations, four other Colocasia species (C. affinis, C. fallax, C. formosana, C. gigantea) and three other aroid genera (represented by Remusatia vivipara, Alocasia brisbanensis and Amorphophallus konjac). Multiple sequence alignments for the intra‐specific comparison revealed nucleotide substitutions (point mutations) at all 30 loci and microsatellite polymorphisms at 14 loci. The primer pairs reported here reveal levels of genetic variation suitable for high‐resolution phylogeographic and evolutionary studies of taro and other closely related aroids. Our results confirm that information on repeat distribution can be used to identify loci suitable for such studies, and we expect that this approach can be used in other plant groups.  相似文献   

15.
The worldwide decline and local extinctions of bumblebees have raised a need for fast and accurate tools for species identification. Morphological characters are often not sufficient, and molecular methods have been increasingly used for reliable identification of bumblebee species. Molecular methods often require high‐quality DNA which makes them less suitable for analysis of low‐quality or older samples. We modified the PCR–RFLP protocol for an efficient and cost‐effective identification of four bumblebee species in the subgenus Bombus s. str. (B. lucorum, B. terrestris, B. magnus and B. cryptarum). We used a short partial mitochondrial COI fragment (446 bp) and three diagnostic restriction enzymes (Hinf I, Hinc II and Hae III) to identify species from degraded DNA material. This approach allowed us to efficiently determine the correct species from all degraded DNA samples, while only a subset of samples 64.6% (31 of 48) resulted in successful amplification of a longer COI fragment (1064 bp) using the previously described method. This protocol can be applied for conservation and management of bumblebees within this subgenus and is especially useful for fast species identification from degraded samples.  相似文献   

16.
Aim To relate genetic diversity to topographic features and to investigate genetic interactions between Eucalyptus species in a local centre of endemism and diversity in south‐eastern Australia. Location Grampian Ranges, Victoria, Australia. Methods We documented chloroplast DNA (cpDNA) variation for a group of endemic Eucalyptus species (E. serraensis, E. verrucata and E. victoriana) that dominate rocky, high‐elevation ridgelines of the Grampian Ranges and for one closely‐related, widespread species (E. baxteri) occupying flanking slopes and valleys. We documented genetic patterns across the landscape using cpDNA microsatellites, and related them to topographic features (exposed west‐facing versus protected east‐facing slopes and valleys). We also determined the extent of local haplotype sharing between populations of endemic species and neighbouring E. baxteri downslope with cpDNA microsatellites, and haplotype sharing between the endemic group and more distantly related species (E. obliqua, E. pauciflora and E. willisii) with sequences of the JLA+ chloroplast region. Results We detected 26 cpDNA microsatellite haplotypes in a relatively small area of c. 20 km × 50 km. Populations of E. baxteri on east‐facing slopes and valleys had greater cpDNA microsatellite diversity than E. baxteri and endemic species on exposed west‐facing slopes. Endemic species frequently shared chloroplast haplotypes with E. baxteri downslope. Sharing of JLA+ haplotypes with species outside the endemic group was mostly restricted to E. victoriana, which had cpDNA more similar to the species from other sections of Eucalyptus (E. obliqua, E. willisii and E. pauciflora). Main conclusions Intensive sampling of related species on small isolated mountain ranges allowed us to relate genetic diversity to fine‐scale habitats and to document extensive local haplotype sharing between species. This study contributes to a general understanding of the environmental conditions that enable plant population persistence by linking concentrations of genetic diversity to particular habitats.  相似文献   

17.
Twenty nuclear microsatellite loci were isolated from a genomic DNA library derived from a free‐ranging red‐bellied brown lemur (Eulemur rubriventer), from the Ranomafana National Park, Madagascar. Population genetic parameters were estimated as baseline values from samples collected from populations harboured in the Ranomafana and Andringitra National Parks. The marker suite will be used in a future study on the population dynamics of this species.  相似文献   

18.
This study reports the isolation and characterization of seven highly polymorphic microsatellite loci in Chthamalus montagui (Crustacea, Cirripedia). The loci were isolated from a library constructed from genomic DNA enriched for CA repeats. The markers yielded three to 43 alleles per locus (mean 16.7) in samples averaging 49 individuals. Observed heterozygosity ranged from 0.08 to 0.58 (mean 0.39). These microsatellite loci will be valuable tools for population genetic studies of this species.  相似文献   

19.
Microsatellite markers were isolated and characterized for Hopea hainanensis Merrill & Chun, an endangered tree species with scattered distribution in Hainan Island and northern Vietnam. Twenty‐six microsatellite markers were developed based on next‐generation sequencing data and were genotyped by capillary electrophoresis on an ABI 3730xl DNA Analyzer. Twelve markers were found to be polymorphic in H. hainanensis. GENODIVE analyses indicated that the number of alleles ranged from 2 to 6 per locus, and the observed and expected heterozygosity varied from 0 to 0.755 and from 0.259 to 0.779, respectively. Primer transferability was tested with Hopea chinensis Hand.‐Mazz. and Hopea reticulata Tardieu, in which 3 and 7 microsatellite markers were found to be polymorphic, separately. The results showed that H. reticulata and H. hainanensis had similar levels of genetic diversity. A neighbor joining dendrogram clustered all individuals into two major groups, one of which was exclusively constituted by H. hainanensis, while the other consisted of two subgroups, corresponding to H. reticulata and H. chinensis, respectively. The 12 polymorphic microsatellite markers could be applied to study genetic diversity, population differentiation, mating system, and fine‐scale spatial genetic structures of H. hainanensis as well as its close relatives, facilitating the conservation and restoration of these endangered but valuable Hopea species.  相似文献   

20.
The genus Tanakaea is a plant genus that consists of one or two evergreen herbaceous species in Japan and China. As rithophytic plant species occur on shaded rocks, the populations are usually isolated and sporadically found in disjunct areas. To evaluate the genetic structure of the species at multiple spatial scales, 10 nuclear and mitochondrial microsatellite markers were developed. The novel markers showed high genetic variations (two to 15 alleles and He from 0.400 to 0.894). Clonal samples were identified with the probability of identity of 9.0E‐8. When evaluated with 11 populations in Japan, significant genetic differentiation between regional population groups was detected (FST = 0.313 between Shikoku and Honshu islands), suggesting they have long been isolated from each other. Overall, these markers will be useful for population genetic research to investigate clonal structure and genetic diversity and levels of genetic differentiation between the geographically isolated populations.  相似文献   

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