975 resultados para MICROSATELLITE MARKERS


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Premise of the study: Microsatellite markers were developed and characterized to investigate genetic diversity and gene flow and to help in conservation efforts for the endangered timber species Plathymenia reticulata. Methods and Results: Eleven microsatellite loci were characterized using 60 adult trees of two populations of P. reticulata from the Atlantic Forest of southern Bahia, Brazil. Of these, nine loci were polymorphic, with an average of 4.39 alleles per locus. The average expected heterozygosity per population ranged from 0.47 to 0.55. The combined exclusion probability was 0.99996. Conclusions: Our results reveal that the microsatellite markers developed in this study are an effective tool for paternity and genetic structure analysis that may be useful for conservation strategies.

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Premise of the study: We developed and characterized nuclear microsatellite markers for Anadenanthera colubrina, a tropical tree species widely distributed in South America. Methods and Results: Leaf samples of mature A. colubrina trees, popularly called "angico," were collected from an area that is greatly impacted by agricultural practices in the region of Ribeirao Preto in Sao Paulo State in southeastern Brazil. Twenty simple sequence repeat (SSR) markers were developed, 14 of which had polymorphic loci. A total of 96 alleles were detected with an average of 6.86 alleles per polymorphic locus. The expected heterozygosity, calculated at polymorphic loci, ranged from 0.18 to 0.83. Finally, we demonstrated that 18 loci were cross-amplified in A. peregrina. Conclusions: A total of 14 polymorphic markers suggest a high potential for genetic diversity, gene flow, and mating system analyses in A. colubrina.

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Premise of the study: Microsatellite primers were developed to investigate genetic diversity and population structure of Qualea grandiflora, a typical species of the Brazilian cerrado. Methods and Results: Eight microsatellite loci were isolated using an enrichment cloning protocol. These loci were tested on a population of 110 individuals of Q. grandiflora collected from a cerrado fragment in Sao Paulo State, Brazil. The loci polymorphism ranges from seven to 19 alleles and the average heterozygosity value is 0.568, while the average polymorphic information content is 0.799. Conclusions: The developed markers were found to be highly polymorphic, indicating their applicability to studies of population genetic diversity in Q. grandiflora

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Premise of the study: A new set of microsatellite or simple sequence repeat (SSR) markers for garlic, an important medicinal spice, was developed to aid studies of genetic diversity and to define efficient strategies for germplasm conservation. Methods and Results: Using a (CT)(8)- and (GT)(8)-enriched library, a total of 16 SSR loci were developed and optimized in garlic. Ten loci were found to be polymorphic after screening 75 accessions. The parameters used to characterize the loci were observed and expected heterozygosity, number of alleles, Shannon Index, and polymorphism information content (PIC). A total of 44 alleles were identified, with an average of 4.4 alleles per loci. The vast majority of loci were moderate to highly informative according to PIC and the Shannon Index. Conclusion: The new SSR markers have the potential to be informative tools for genetic diversity, allele mining, mapping and associative studies, and in the management and conservation of garlic collections.

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The Adriatic sturgeon, Acipenser naccarii (Bonaparte, 1836), is a highly threatened species due to human activities, particularly overfishing and habitat destruction. Its peculiar ecology and biology (restricted areal and anadromy) makes this species particularly vulnerable. In March 2010 the IUCN has identified the Adriatic sturgeon as a critically endangered species according to the Red List of Threatened Species. Due to its rapid decline, starting from the 80s, at present there is no evidence of natural reproduction in wild environment, which makes the Adriatic sturgeon dependenton captive breeding programs that need to be improved in order to be effective for the survival of the species. For this purpose this study aims to characterize artificial restocking population of Adriatic sturgeon, with both genetic and physiological analysis in order to establish an efficient restocking program for future reproductions. The research is structured on two levels: First genetically, by analyzing 9 microsatellite loci. This gives information relatively about parent allocation and kinship between individuals that were sampled for this study. Hence to predict which reproduction events are the most optimal in terms of incrementing genetic diversity, by the estimation of multilocus pairwise band sharing coefficients. Second step, physiological analysis: testosterone (T) concentration levels in each individual were measured for sexing, without sacrificing the lives of the animals with the use of an invasive examination of the gonads. The combination of interdisciplinary analysis is important to obtain an overall picture in order to indicate the main broodstock participating in reproduction events and future optimal potential participants, in order to ensure a valid management for restocking program and their monitoring.

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Background: The shrimp Nematocarcinus lanceopes Bate, 1888 is found in the deep sea around Antarctica and sub-Antarctic islands. Previous studies on mitochondrial data and species distribution models provided evidence for a homogenous circum-Antarctic population of N. lanceopes. However, to analyze the fine-scale population genetic structure and to examine influences of abiotic environmental conditions on population composition and genetic diversity, a set of fast evolving nuclear microsatellite markers is required. Findings: We report the isolation and characterization of nine polymorphic microsatellite markers from the Antarctic deep-sea shrimp species Nematocarcinus lanceopes (Crustacea: Decapoda: Caridea). Microsatellite markers were screened in 55 individuals from different locations around the Antarctic continent. All markers were polymorphic with 9 to 25 alleles per locus. The observed heterozygosity ranged from 0.545 to 0.927 and the expected heterozygosity from 0.549 to 0.934. Conclusions: The reported markers provide a novel tool to study genetic structure and diversity in Nematocarcinus lanceopes populations in the Southern Ocean and monitor effects of ongoing climate change in the region on the populations inhabiting these.

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The ecologically important stream invertebrate Gammarus fossarum is a morphospecies that includes at least three genetically differentiated biological species. We developed ten microsatellite markers and tested them in a total of 208 individuals from all three known cryptic species (types A, B and C). All markers were polymorphic and successfully amplified in type A, nine in type B and five in type C. There were up to 11 alleles per marker and species.

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Neospora caninum is one of the most significant parasitic organisms causing bovine abortion worldwide. Despite the economic impact of this infection, relatively little is known about the genetic diversity of this parasite. In this study, using Nc5 and ITS1 nested PCR, N. caninum has been detected in 12 brain samples of aborted fetuses from 298 seropositive dairy cattle collected from four different regions in Tehran, Iran. These specimen (Nc-Iran) were genotyped in multilocus using 9 different microsatellite markers previously described (MS4, MS5, MS6A, MS6B, MS7, MS8, MS10, MS12 and MS21). Microsatellite amplification was completely feasible in 2 samples, semi-completely in 8 samples, and failed in 2 samples. Within the two completely performed allelic profiles of Nc-Iran strains, unique multilocus profiles were obtained for both and novel allelic patterns were found in the MS8 and MS10 microsatellite markers. The Jaccard's similarity index showed significant difference between these two strains and from other standard isolates derived from GenBank such as Nc-Liv, Nc-SweB1, Nc-GER1, KBA1, and KBA2. All samples originating from the same area showed identical allelic numbers and a correlation between the number of repeats and geographic districts was observed.

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Background Simple Sequence Repeats (SSRs) are widely used in population genetic studies but their classical development is costly and time-consuming. The ever-increasing available DNA datasets generated by high-throughput techniques offer an inexpensive alternative for SSRs discovery. Expressed Sequence Tags (ESTs) have been widely used as SSR source for plants of economic relevance but their application to non-model species is still modest. Methods Here, we explored the use of publicly available ESTs (GenBank at the National Center for Biotechnology Information-NCBI) for SSRs development in non-model plants, focusing on genera listed by the International Union for the Conservation of Nature (IUCN). We also search two model genera with fully annotated genomes for EST-SSRs, Arabidopsis and Oryza, and used them as controls for genome distribution analyses. Overall, we downloaded 16 031 555 sequences for 258 plant genera which were mined for SSRsand their primers with the help of QDD1. Genome distribution analyses in Oryza and Arabidopsis were done by blasting the sequences with SSR against the Oryza sativa and Arabidopsis thaliana reference genomes implemented in the Basal Local Alignment Tool (BLAST) of the NCBI website. Finally, we performed an empirical test to determine the performance of our EST-SSRs in a few individuals from four species of two eudicot genera, Trifolium and Centaurea. Results We explored a total of 14 498 726 EST sequences from the dbEST database (NCBI) in 257 plant genera from the IUCN Red List. We identify a very large number (17 102) of ready-to-test EST-SSRs in most plant genera (193) at no cost. Overall, dinucleotide and trinucleotide repeats were the prevalent types but the abundance of the various types of repeat differed between taxonomic groups. Control genomes revealed that trinucleotide repeats were mostly located in coding regions while dinucleotide repeats were largely associated with untranslated regions. Our results from the empirical test revealed considerable amplification success and transferability between congenerics. Conclusions The present work represents the first large-scale study developing SSRs by utilizing publicly accessible EST databases in threatened plants. Here we provide a very large number of ready-to-test EST-SSR (17 102) for 193 genera. The cross-species transferability suggests that the number of possible target species would be large. Since trinucleotide repeats are abundant and mainly linked to exons they might be useful in evolutionary and conservation studies. Altogether, our study highly supports the use of EST databases as an extremely affordable and fast alternative for SSR developing in threatened plants.

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Seventeen polymorphic microsatellite markers were isolated and characterized in Arion vulgaris/lusitanicus, which belongs to the worst European slug pests with serious economic and ecological impact. These markers were tested on 23 individuals collected in a population in Switzerland. Numbers of alleles ranged from 2 to 14 per locus, observed and expected heterozygosities ranged from 0.174 to 0.87, and from 0.162 to 0.903, respectively. These loci were also successfully amplified and were polymorphic in the closely related species A. rufus and A. ater. These loci represent the first highly polymorphic nuclear markers described for A. vulgaris and pave the way for population genetics and molecular ecology research of the important Arion pest slugs.

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Pedro Giménez' is a white criolla variety cropped in Argentina, mainly in Mendoza and San Juan, being the most planted white variety destined for wine making in the country. Its origin remains unknown, as well as its relationship with Spanish variety 'Pedro Ximénez', mostly grown in Jerez, Spain. Previous works have probed that most of Criollas varieties existing in America at the moment, are the offspring of 'Muscat of Alexandria' x 'Criolla Chica'. The aim of the present work was to compare 'Pedro Giménez' with the Spanish variety 'Pedro Ximénez', and to establish its degree of relatedness to 'Muscat of Alexandria' and 'Criolla Chica'. Therefore we used a set of 18 nuclear SSR loci and 3 chloroplast SSR loci. 'Pedro Giménez' shared only 38% of the alleles under analysis with 'Pedro Ximénez', indicating that they are indeed two different varieties. In all 18 polymorphic nuclear SSR loci 'Pedro Giménez' shared 50% of its alleles with 'Muscat of Alexandria', while the other 50% of the alleles present in 'Pedro Giménez' were also present in 'Criolla Chica'. This data, along with those from the chloroplast SSR analysis, strongly suggest that 'Pedro Giménez' is the progeny of 'Muscat of Alexandria' x 'Criolla Chica', being the latest one the most likely female progenitor.