Identified Microsatellite Loci Research Articles

The genetic diversity of Oncomelania hupensis robertsoni, intermediate hosts of Schistosoma japonicum in hilly regions of China, using microsatellite markers

BackgroundThe elimination of schistosomiasis remains a challenging task, with current measures primarily focused on the monitoring and control of Oncomelania hupensis (O. hupensis) snail, the sole intermediate host of Schistosome japonicum. Given the emerging, re-emerging, and persistent habitats of snails, understanding their genetic diversity might be essential for their successful monitoring and control. The aims of this study were to analyze the genetic diversity of Oncomelania hupensis robertsoni (O. h. robertsoni) using microsatellite DNA markers; and validate the applicability of previously identified microsatellite loci for O. hupensis in hilly regions.MethodsA total of 17 populations of O. h. robertsoni from Yunnan Province in China were selected for analysis of genetic diversity using six microsatellite DNA polymorphic loci (P82, P84, T4-22, T5-11, T5-13, and T6-27).ResultsThe number of alleles among populations ranged from 0 to 19, with an average of 5. The average ranges of expected (He) and observed (Ho) heterozygosity within populations were 0.506 to 0.761 and 0.443 to 0.792, respectively. The average fixation index within the population ranged from – 0.801 to 0.211. The average polymorphic information content (PIC) within the population ranged from 0.411 to 0.757, appearing to be polymorphic for all loci (all PIC > 0.5), except for P28 and P48. A total of 68 loci showed significant deviations from Hardy-Weinberg equilibrium (P < 0.05), and pairwise Fst values ranged from 0.051 to 0.379. The analysis of molecular variance indicated that 88% of the variation occurred within snail populations, whereas 12% occurred among snail populations. Phylogenetic trees and principal coordinate analysis revealed two distinct clusters within the snail population, corresponding to “Yunnan North” and “Yunnan South”.ConclusionsO. h. robertsoni exhibited a relatively high level of genetic differentiation, with variation chiefly existing within snail populations. All snail in this region could be separated into two clusters. The microsatellite loci P82 and P84 might not be suitable for classification studies of O. hupensis in hilly regions. These findings provided important information for the monitoring and control of snail, and for further genetic diversity studies on snail populations.Graphical

IDENTIFICATION OF MICROSATELLITE LOCI ASSOCIATED WITH EMBRYOGENIC POTENTIAL IN WHEAT GENOTYPES IN ANTHER CULTURE IN VITRO

In order to identify microsatellite loci that can be used as markers in screening for responsiveness in the in vitro&#x0D; anther culture, the efficiency of androgenesis in vitro was evaluated in 24 wheat genotypes. The forms contrasting in responsiveness in the in vitro anther culture were identified, and four F2 segregating populations were obtained on their basis. The study of interlinear polymorphism by 20 microsatellite loci located on chromosomes 5A and 5B was carried out. It was found that the cleavage by the ability to embryogenesis coincides with the cleavage by the alleles of the Xgwm371 locus: the 169 bp allele is associated with the ability to embryogenesis; the 185 bp allele — with the absence of such an ability or extremely low embryoid yield in the anther culture in vitro.

Development of novel microsatellite marker panel in threatened tetraploid mahseer, Tor tor (Hamilton 1822) for insights into its genetic diversity and population structure

BackgroundTor tor (Hamilton 1922), a natural polyploid fish species, is commonly known as the red-fin or deep bodied mahseer and is the type species of the Tor genus. It was assessed as ‘Near Threatened’ in the IUCN Red List, due to rapidly declining populations in wild and recently reassessed as Data Deficient. To generate the genetic structure information in this species, co-dominant markers face polyploidy specific hitches in genotyping, such as auto/tetrasomy, double reduction and missing dosage information. ObjectiveIn the present study, a total of 25 polymorphic microsatellite loci was developed through long- read single molecule, real time (SMRT) sequencing technology, to genotype 139 T. tor samples from six natural riverine populations of India, to determine intra-specific genetic variation in this species. ResultsUpon sequencing 1.5 kb SMRT bell library, the clustering and assembly of high-quality CCS reads resulted into 9746 contigs and 2129 contained repeat sequences. The majority of repeats were dinucleotide (67.8%), followed by trinucleotide (21.4%) and tetranucleotide (10.7%). Out a total of 118 SSR loci primers designed, 25 loci showed polymorphism. The microsatellite genotype analyses with these loci indicated T. tor as an auto-tetraploid, with tetrasomy segregation and occurrence of double reduction. The microsatellite loci identified were highly polymorphic (average PIC 0.6687).. The genetic diversity parameters, observed and expected heterozygosities ranged from 0.1268 to 0.5047 and from 0.4989 to 0.9212, respectively, whereas inbreeding (FIS) values from 0.2334 to 0.8379. The average ρ statistics value of 0.0739 (p = 0.00) indicated the presence of genetic structure in the natural population, and along with pair-wise ρ statistics and DAPC analysis pointed to the occurrence of three genetic stocks. ConclusionThe identified microsatellite loci were found to be useful in generating information on genetic diversity and fine scale population structure of tetraploid T. tor, which would be valuable for conservation and management of this threatened species.

Mining the red deer genome (CerEla1.0) to develop X-and Y-chromosome-linked STR markers.

Microsatellites are widely applied in population and forensic genetics, wildlife studies and parentage testing in animal breeding, among others, and recently, high-throughput sequencing technologies have greatly facilitated the identification of microsatellite markers. In this study the genomic data of Cervus elaphus (CerEla1.0) was exploited, in order to identify microsatellite loci along the red deer genome and for designing the cognate primers. The bioinformatics pipeline identified 982,433 microsatellite motifs genome-wide, assorted along the chromosomes, from which 45,711 loci mapped to the X- and 1096 to the Y-chromosome. Primers were successfully designed for 170,873 loci, and validated with an independently developed autosomal tetranucleotide STR set. Ten X- and five Y-chromosome-linked microsatellites were selected and tested by two multiplex PCR setups on genomic DNA samples of 123 red deer stags. The average number of alleles per locus was 3.3, and the average gene diversity value of the markers was 0.270. The overall observed and expected heterozygosities were 0.755 and 0.832, respectively. Polymorphic Information Content (PIC) ranged between 0.469 and 0.909 per locus with a mean value of 0.813. Using the X- and Y-chromosome linked markers 19 different Y-chromosome and 72 X-chromosome lines were identified. Both the X- and the Y-haplotypes split to two distinct clades each. The Y-chromosome clades correlated strongly with the geographic origin of the haplotypes of the samples. Segregation and admixture of subpopulations were demonstrated by the use of the combination of nine autosomal and 16 sex chromosomal STRs concerning southwestern and northeastern Hungary. In conclusion, the approach demonstrated here is a very efficient method for developing microsatellite markers for species with available genomic sequence data, as well as for their use in individual identifications and in population genetics studies.

Genetic parameters of the Chukchi breed populations in generational change

The purpose of the work is to study the genetic characteristics of reindeer populations in the Chukotka Autonomous Region using DNA microsatellites. Genetic monitoring data for 2013 and 2018 are presented (the interval of one generation). In the genetic parameters of populations statistically significant differences were found. Samples are characterized by a large number of active alleles of breed diversity. The average number of alleles per locus ranged from 7.7 to 9.95. Indices of heterozygosity in the studied groups of deer are from 0.851 to 0.887 - indicate the prosperous condition of the populations of the Chukchi breed by genetic heterogeneity. The differentiation of livestock is influenced by inter-farm and inter-herd exchange of the allele pool. Criteria for the genetic similarity of the selective sample populations of 2013 and 2018 according to the frequencies of the ISSR markers were in the range from 0.852 to 0.993, which indicates the stability of the gene pools of the studied deer groups. Eco-geographical and economic conditions affect the frequency of ISSR markers with a force of ηx2 = 67-70.4%, being the main factor of intraspecific differentiation. According to the identified microsatellite loci, the populations of the Chukchi breed are in a state of genetic equilibrium. Factors which stabilize the genetic structure of the populations of the Chukchi breed are free crosses typical for reindeer, a large number of males involved in reproduction. Noting that the number of deer of the Chukchi breed is declining, constant monitoring of its gene pool is necessary, which provides the stability of populations.

Development of 18 microsatellite markers for Salvia pratensis.

PremiseMicrosatellite markers were developed for the perennial herb Salvia pratensis (Lamiaceae), a species representative of European dry grasslands. The development of microsatellite markers is needed for genetic and phylogeographical studies of species from the genus Salvia.Methods and ResultsWe used low‐coverage Illumina sequencing to identify microsatellite loci. Based on these data, we have developed 18 polymorphic microsatellite markers with the number of alleles per locus ranging from two to 15. The levels of observed and expected heterozygosity ranged from 0.05 to 0.95 and from 0.05 to 0.89, respectively. The majority of the markers successfully cross‐amplified in other Salvia species.ConclusionsThe markers were shown to be suitable for population genetic and phylogeographic studies in S. pratensis as well as in related species (S. aethiopis, S. austriaca, S. glutinosa, S. nemorosa, S. nutans, and S. verticillata) and will be used in the broader context to trace the origins of European dry grasslands.

Identification and evaluation of a core microsatellite panel for use in white-tailed deer (Odocoileus virginianus)

BackgroundMicrosatellite loci have been used extensively over the past two decades to study the genetic characteristics of non-model species. The ease of microsatellite development and ability to adapt markers from related species has led to the proliferation of available markers for many commonly studied species. Because it is often infeasible to genotype individuals across all available loci, researchers generally rely on subsets of markers. Marker choice can bias inferences made using disparate suites of loci. This has been a primary motivation for efforts to identify uniform marker panels. Here, we use the geographic distribution of previous studies to identify microsatellite loci for white-tailed deer (Odocoileus virginianus) with the potential for widespread use, and we evaluate the effectiveness of this panel in a portion of the range where few previous studies have been conducted. The purpose was to consolidate the numerous genetic resources for this species into a manageable panel and to provide a uniform methodology that improves comparisons between past and future studies.ResultsWe reviewed microsatellite panels from 58 previous or ongoing projects and identified 106 candidate loci. We developed a multiplex protocol and evaluated the efficacy of 17 of the most commonly used loci using 720 DNA samples collected from the Mid-Atlantic region of the United States of America. Amplification errors were detected in six of these loci. The 11 remaining loci were highly polymorphic, exhibited low frequencies of null alleles, and were easy to interpret with the aid of allele binning software.ConclusionsThe development of broadly-applicable, core microsatellite panels has the potential to improve repeatability and comparative ability for commonly studied species. The properties of the consolidated 11 microsatellite panel suggest that they are applicable for many common research objectives for white-tailed deer. The geographic distribution of previous studies using these markers provides a greater degree of confidence regarding the robustness to common sources of error related to amplification anomalies, such as null alleles, relative to loci with more limited use. While this does not replace further evaluation of genotyping errors, it does provide a common platform that benefits future research studies.

A new Multi Locus Variable Number of Tandem Repeat Analysis Scheme for epidemiological surveillance of Xanthomonas vasicola pv. musacearum, the plant pathogen causing bacterial wilt on banana and enset.

Xanthomonas vasicola pv. musacearum (Xvm) which causes Xanthomonas wilt (XW) on banana (Musa accuminata x balbisiana) and enset (Ensete ventricosum), is closely related to the species Xanthomonas vasicola that contains the pathovars vasculorum (Xvv) and holcicola (Xvh), respectively pathogenic to sugarcane and sorghum. Xvm is considered a monomorphic bacterium whose intra-pathovar diversity remains poorly understood. With the sudden emergence of Xvm within east and central Africa coupled with the unknown origin of one of the two sublineages suggested for Xvm, attention has shifted to adapting technologies that focus on identifying the origin and distribution of the genetic diversity within this pathogen. Although microbiological and conventional molecular diagnostics have been useful in pathogen identification. Recent advances have ushered in an era of genomic epidemiology that aids in characterizing monomorphic pathogens. To unravel the origin and pathways of the recent emergence of XW in Eastern and Central Africa, there was a need for a genotyping tool adapted for molecular epidemiology. Multi-Locus Variable Number of Tandem Repeat Analysis (MLVA) is able to resolve the evolutionary patterns and invasion routes of a pathogen. In this study, we identified microsatellite loci from nine published Xvm genome sequences. Of the 36 detected microsatellite loci, 21 were selected for primer design and 19 determined to be highly typeable, specific, reproducible and polymorphic with two- to four- alleles per locus on a sub-collection. The 19 markers were multiplexed and applied to genotype 335 Xvm strains isolated from seven countries over several years. The microsatellite markers grouped the Xvm collection into three clusters; with two similar to the SNP-based sublineages 1 and 2 and a new cluster 3, revealing an unknown diversity in Ethiopia. Five of the 19 markers had alleles present in both Xvm and Xanthomonas vasicola pathovars holcicola and vasculorum, supporting the phylogenetic closeliness of these three pathovars. Thank to the public availability of the haplotypes on the MLVABank database, this highly reliable and polymorphic genotyping tool can be further used in a transnational surveillance network to monitor the spread and evolution of XW throughout Africa.. It will inform and guide management of Xvm both in banana-based and enset-based cropping systems. Due to the suitability of MLVA-19 markers for population genetic analyses, this genotyping tool will also be used in future microevolution studies.

Transcriptome-wide mining, characterization, and development of microsatellite markers in Lychnis kiusiana (Caryophyllaceae)

BackgroundLychnis kiusiana Makino is an endangered perennial herb native to wetland areas in Korea and Japan. Despite its conservational and evolutionary significance, population genetic resources are lacking for this species. Next-generation sequencing has been accepted as a rapid and cost-effective solution for the identification of microsatellite markers in nonmodel plants.ResultsUsing Illumina HiSeq 2000 sequencing technology, we assembled 67,498,600 reads into 91,900 contigs and identified 11,403 microsatellite repeat motifs in 9563 contigs. A total of 4510 microsatellite-containing transcripts had Gene Ontology (GO) annotations, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified 124 pathways with significant scores. Many microsatellites in the L. kiusiana leaf transcriptome were linked to genes involved in the plant response to light intensity, salt stress, temperature stimulus, and nutrient and water deprivation. A total of 12,486 single-nucleotide polymorphisms (SNPs) were identified on transcripts harboring microsatellites. The analysis of nucleotide substitution rates for 2389 unigenes indicated that 39 genes were under strong positive selection. The primers of 6911 microsatellites were designed, and 40 of 50 selected primer pairs were consistently and successfully amplified from 51 individuals. Twenty-five of these were polymorphic, and the average number of alleles per SSR locus was 6.96, with a range from 2 to 15. The observed and expected heterozygosities ranged from 0.137 to 0.902 and 0.131 to 0.827, respectively, and locus-specific FIS estimates ranged from − 0.116 to 0.290. Eleven of the 25 primer pairs were successfully amplified in three additional species of Lychnis: 56% in L. wilfordii, 64% in L. cognata and 80% in L. fulgens.ConclusionsThe transcriptomic SSR markers of Lychnis kiusiana provide a valuable resource for understanding the population genetics, evolutionary history, and effective conservation management of this species. Furthermore, the identified microsatellite loci linked to the annotated genes should be useful for developing functional markers of L. kiusiana. The developed markers represent a potentially valuable source of transcriptomic SSR markers for population genetic analyses with moderate levels of cross-taxon portability.

Analysis of microsatellite loci in tree of heaven (Ailanthus altissima (Mill.) Swingle) using SSR-GBS

Microsatellite markers are still the marker of choice for many research questions in the field of forest genetics. However, the number of available markers is often low for species that have not been studied intensively like the tree of heaven (Ailanthus altissima). During the last decade, next-generation sequencing (NGS) has offered advanced techniques for efficiently identifying microsatellite markers and accurately genotyping samples. Here, we identify new microsatellite markers for the tree of heaven by applying an NGS-based method using the Illumina MiSeq platform. NGS technology was proved to be an effective method for fast and cost-efficient identification of microsatellite markers by implementing a genotyping-by-sequencing approach based on Illumina amplicon sequencing (SSR-GBS). We screened three populations from Eastern Austria for genetic variation at 19 newly identified microsatellite loci. We tested two different genotyping approaches: (1) considering only allele lengths (forming a so-called “allele length dataset”), (2) taking also single nucleotide polymorphisms (SNPs) within the amplified fragments into account (forming a so-called “SNP dataset”). The results revealed higher values for all genetic diversity parameters, as well as a better resolution of genetic assignment, when the latter approach was followed. Thus, by taking advantage of sequence information which is provided by SSR-GBS, one may achieve considerable gains in performance using the same marker set. The developed markers provide a cost-efficient tool for genotyping populations of tree of heaven and the approach presented here promises to be of high value for medium throughput genotyping applications in non-model forest tree species. We will use this method to widen the perspectives for further population genetic investigations of the tree of heaven.

New Microsatellite Markers for Two Sympatric Tinamou Species, the Ornate Tinamou (Nothoprocta ornata) and Darwin's Nothura (Nothura darwinii)

Tinamous (Tinamidae) represent one of the most ancient living avian lineages but their life history traits are relatively unstudied. Here we identified microsatellite loci for two sympatric tinamou species, the Ornate Tinamou ( Nothoprocta ornata) and the Darwin's Nothura ( Nothura darwinii) from low coverage Illumina sequencing of genomic DNA. The experiment yielded a large number of candidate loci. We designed primers and tested them for successful amplification in 1 to 2 populations of the target species, tested for deviation from the Hardy–Weinberg equilibrium and the presence of null alleles, the levels of polymorphism and potential cross-amplification. All 30 and 24 loci amplified consistently, in the Ornate Tinamou and in Darwin's Nothura, respectively. In the Ornate Tinamou, 25 loci were polymorphic and in the Darwin's Nothura 12, with 2 to 14 alleles per locus in both species. The expected heterozygosity ranged from 0.054 to 0.917 in the Ornate Tinamou and from 0.044 to 0.908 in the Darwin's Nothura. 23 (40%) of 54 loci were successfully cross-amplified. These newly discovered, polymorphic microsatellite loci represent a valuable tool for future studies on social behaviour, parentage and genetic population structure in tinamous.

Microsatellite discovery in an insular amphibian (Grandisonia alternans) with comments on cross-species utility and the accuracy of locus identification from unassembled Illumina data

The Seychelles archipelago is unique among isolated oceanic islands because it features an endemic radiation of caecilian amphibians (Gymnophiona). In order to develop population genetics resources for this system, we identified microsatellite loci using unassembled Illumina MiSeq data generated from a genomic library of Grandisonia alternans, a species that occurs on multiple islands in the archipelago. Applying a recently described method (PALFINDER) we identified 8001 microsatellite loci that were potentially informative for population genetics analyses. Of these markers, we screened 60 loci using five individuals, directly sequenced several amplicons to confirm their identity, and then used eight loci to score allele sizes in 64 G. alternans individuals originating from five islands. A number of these individuals were sampled using non-lethal methods, demonstrating the efficacy of non-destructive molecular sampling in amphibian research. Although two loci satisfied our criteria as diploid, neutrally evolving loci with the statistical power to detect population structure, our success in identifying reliable loci was very low. Additionally, we discovered some issues with primer redundancy and differences between Illumina and Sanger sequences that suggest some Illumina-inferred loci are invalid. We investigated cross-species utility for eight loci and found most could be successfully amplified, sequenced and aligned across other species and genera of caecilians from the Seychelles. Thus, our study in part supported the validity of using PALFINDER with unassembled reads for microsatellite discovery within and across species, but importantly identified major limitations to applying this approach to small datasets (ca. 1 million reads) and loci with small tandem repeat sizes.

CROSS-SPECIES AMPLIFICATION STUDY OF Tor douronensis AND Tor tambroides USING MICROSATELLITES FROM OTHER CYPRINIDS

This study examined twenty six microsatellite primers developed from three cyprinid fishes (Cyprinus carpio, Barbus barbus and Barbonymus gonionotus) in two indigenous mahseer, Tor douronensis and T. tambroides. A total of 10 (38%) and 12 (46%) primers were successfully amplified producing four and five polymorphic loci in T. douronensis and T. tambroides, respectively. The number of alleles per locus ranging from 2 to 5 and 2 to 7 in T. douronensis and T. tambroides, respectively. A significant deviation from Hardy-Weinberg equilibrium (HWE) was observed at three loci (Barb37, Barb59 and Barb62) in one or more populations in T. tambroides while two loci (Barb37 and Barb62) were deviated in T. douronensis population of Batang Ai. Bayesian cluster analysis performed with STRUCTURE showed that the most likely K value identified was K = 2 with no evidence of population substructuring, similar to those identified by the UPGMA dendrogram. The low genetic distances among populations were also supported by low interpopulation genetic differences (FST) among pairwise populations in both mahseer. Overall, the identified microsatellite loci exhibit promise for use in fine scale population structure analysis of T. douronensis and T. tambroides natural populations.

Identification of robust microsatellite markers for wild pig fecal DNA

ABSTRACTCollection of fecal samples for use in a genetic capture‐mark‐recapture framework has become popular as a noninvasive method of monitoring wildlife populations. A major caveat to this process, however, is that fecal samples often yield low quality DNA that is prone to genotyping errors, potentially leading to biases in population parameter estimation. Therefore, considerable care is required to identify robust genetic markers, especially in hot or humid conditions that may accelerate DNA degradation. We identified microsatellite loci in wild pig (Sus scrofa) fecal samples that were robust and informative within warm, humid ecosystems. To examine how degradation affected genotyping success, we sampled pig feces across 5 days and calculated how the number of quantitative polymerase chain reaction (qPCR) cycles required to reach the fluorescent threshold (Ct) changed over time. We identified 17 microsatellite loci that had high polymorphism and amplification success and low genotyping error rates (0–0.050 per locus). In the degradation experiment, Ct increased over the 5 days, but in the absence of rain, the majority of samples produced accurate genotypes after 5 days (2,211/2,550 genotypes). Based on the high amplification success and low error rates, even after 5 days of exposure to warm, humid conditions, these loci are useful for estimating population parameters in pig fecal samples. © 2016 The Wildlife Society.

Characterization of 19 microsatellite loci in the clonal monkshood Aconitum kusnezoffii (Ranunculaceae).

Premise of the study:Microsatellite loci were isolated and characterized from Aconitum kusnezoffii (Ranunculaceae) to estimate male and female reproductive success and evaluate the effects of clonal growth on sexual reproduction.Methods and Results:A genomic enrichment approach was used to develop microsatellite markers. In three investigated A. kusnezoffii populations, a total of 19 microsatellite loci were successfully amplified, and 13 of these loci were polymorphic. Most of the primer pairs designed for the identified loci also amplified corresponding microsatellite loci in A. barbatum var. puberulum and A. alboviolaceum.Conclusions:The identified microsatellite loci will be useful for quantifying male and female fitness in A. kusnezoffii and evaluating the effects of clonal growth on sexual reproduction.

A new resource for the development of SSR markers: Millions of loci from a thousand plant transcriptomes.

Premise of the study:The One Thousand Plant Transcriptomes Project (1KP, 1000+ assembled plant transcriptomes) provides an enormous resource for developing microsatellite loci across the plant tree of life. We developed loci from these transcriptomes and tested their utility.Methods and Results:Using software packages and custom scripts, we identified microsatellite loci in 1KP transcriptomes. We assessed the potential for cross-amplification and whether loci were biased toward exons, as compared to markers derived from genomic DNA. We characterized over 5.7 million simple sequence repeat (SSR) loci from 1334 plant transcriptomes. Eighteen percent of loci substantially overlapped with open reading frames (ORFs), and electronic PCR revealed that over half the loci would amplify successfully in conspecific taxa. Transcriptomic SSRs were approximately three times more likely to map to translated regions than genomic SSRs.Conclusions:We believe microsatellites still have a place in the genomic age—they remain effective and cost-efficient markers. The loci presented here are a valuable resource for researchers.

Analysis of Allelic Diversity and Genetic Relationships Among Cultivated Mangosteen (Garcinia mangostana L.) in Java, Indonesia Using Microsatellite Markers and Morphological Characters

The genetic variation and relationships of the mangosteen (Garcinia mangostana L.) were observed across mangosteen populations in Java, Indonesia using newly identified microsatellite loci and morphological characters. In this study, we developed an improved protocol to isolate microsatellite loci, named Selective Repeats from AFLP Sequence, by using a hybridized membrane. Twenty microsatellite loci were evaluated using 78 individuals from five mangosteen populations, and we successfully amplified four closely related Garcinia species, including G. malaccensis, G. hombroniana, G. celebica, and G. porrecta. Eight loci were monomorphic and the others were polymorphic. Sixty-nine alleles were found, with 3.491 per locus on an average. Genetic diversity (Hʹ) was calculated with an average across loci within population (HʹS) as 0.39, an average loci across many populations (HʹT) as 0.444, and genetic differentiation (FʹST) as 0.147. Furthermore, based on morphological characters, mangosteen individuals from four populations including Leuwiliang, Wanayasa, Puspahiang, and Kaligesing also had morphologically distinct fruit weight, rind weight, and rind thickness among populations. The study also elucidated the dispersal pattern of mangosteen in Java; the source of the genotype mangosteen in Java population was the Wanayasa population. In addition, we found evidence of tetraploidy in mangosteen. These results have potential applications in future breeding, conservation studies, and genetic assessment of mangosteen and their closely related species.

Distribution, function and evolution characterization of microsatellite in Sargassum thunbergii (Fucales, Phaeophyta) transcriptome and their application in marker development.

Using transcriptome data to mine microsatellite and develop markers has growingly become prevalent. However, characterizing the possible function of microsatellite is relatively rare. In this study, we explored microsatellites in the transcriptome of the brown alga Sargassum thunbergii and characterized the frequencies, distribution, function and evolution, and developed primers to validate these microsatellites. Our results showed that Tri-nucleotide is the most abundant, followed by di- and mono-nucleotide. The length of microsatellite was significantly affected by the repeat motif size. The density of microsatellite in the CDS region is significantly lower than that in the UTR region. The annotation of the transcripts containing microsatellite showed that 573 transcripts have GO terms and can be categorized into 42 groups. Pathways enrichment showed that microsatellites were significantly overrepresented in the genes involved in pathways such as Ubiquitin mediated proteolysis, RNA degradation, Spliceosome, etc. Primers flanking 961 microsatellite loci were designed, and among the 30 pairs of primer selected randomly for availability test, 23 were proved to be efficient. These findings provided new insight into the function and evolution of microsatellite in transcriptome, and the identified microsatellite loci within the annotated gene will be useful for developing functional markers in S. thunbergii.

Screening of repetitive motifs inside the genome of the flat oyster (Ostrea edulis): Transposable elements and short tandem repeats

The flat oyster (Ostrea edulis) is one of the most appreciated molluscs in Europe, but its production has been greatly reduced by the parasite Bonamia ostreae. Here, new generation genomic resources were used to analyse the repetitive fraction of the oyster genome, with the aim of developing molecular markers to face this main oyster production challenge. The resulting oyster database, consists of two sets of 10,318 and 7159 unique contigs (4.8Mbp and 6.8Mbp in total length) representing the oyster's genome (WG) and haemocyte transcriptome (HT), respectively. A total of 1083 sequences were identified as TE-derived, which corresponded to 4.0% of WG and 1.1% of HT. They were clustered into 142 homology groups, most of which were assigned to the Penelope order of retrotransposons, and to the Helitron and TIR DNA-transposons. Simple repeats and rRNA pseudogenes, also made a significant contribution to the oyster's genome (0.5% and 0.3% of WG and HT, respectively).The most frequent short tandem repeats identified in WG were tetranucleotide motifs while trinucleotide motifs were in HT. Forty identified microsatellite loci, 20 from each database, were selected for technical validation. Success was much lower among WG than HT microsatellites (15% vs 55%), which could reflect higher variation in anonymous regions interfering with primer annealing. All microsatellites developed adjusted to Hardy–Weinberg proportions and represent a useful tool to support future breeding programmes and to manage genetic resources of natural flat oyster beds.

Isolation and characterization of twelve polymorphic microsatellite loci for Hypochaeris catharinensis (Asteraceae) and cross-amplification in related species.

In this study, we describe the development and screening of an enriched genomic DNA library aiming to identify microsatellite loci in Hypochaeris catharinensis, an endemic species from southern Brazil. Twelve polymorphic microsatellite loci tested in a sample of 60 individuals from three different populations of H. catharinensis, identified 98 alleles with an average of 8.17 alleles per locus. The average polymorphic information content (PIC) varied from 0.098 to 0.757, with five loci exhibiting significant deviation from Hardy–Weinberg equilibrium (HWE). Transferability test for cross-amplification was done in 10 related Hypochaeris species with a rate of success ranging from 12 loci, for H. petiolaris and H. varigata, to six loci for H. patagonica. These microsatellite loci will provide valuable information for studying genetic diversity, population genetic structure, conservation biology and for understanding the past demographic events of H. catharinensis and other related species of Hypochaeris. Hypochaeris is considered as a biological model to understand evolutionary processes in the vascular flora of South America, particularly from the temperate portion of the continent. As suggested by molecular clock dating, the South American species of Hypochaeris was derived from a common ancestor from northwest Africa that arrived in the continent between 3.5 and 0.25 mya by long-distance dispersal