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opencc-zeroSep 2021View details →

Tool for genomic selection and breeding to evolutionary adaptation: Development of a 100K single nucleotide polymorphism array for the honey bee

High-throughput high density genotyping arrays continue to be a fast, accurate, and cost-effective method for genotyping thousands of polymorphisms in high numbers of individuals. Here we have developed a new high-density SNP genotyping array (103 270 SNPs) for honey bees, one of the most ecologically and economically important pollinators worldwide. SNPs were detected by conducting whole genome resequencing of 61 honey bee drones (haploid males) from throughout Europe. Selection of SNPs for the chip was done in multiple steps using several criteria. The majority of SNPs were selected based on their location within known candidate regions or genes underlying a range of honey bee traits, including hygienic behaviour against pathogens, foraging and subspecies. Additionally, markers from a GWAS of hygienic behaviour against the major honey bee parasite Varroa destructor, were brought over. The chip also includes SNPs associated with each of three major breeding objectives - honey yield, gentleness and Varroa resistance. We validated the chip and make recommendations for its use by determining error rates in repeat genotypings, examining the genotyping performance of different tissues, and by testing how well different sample types represent the queen's genotype. The latter is a key test because it is highly beneficial to be able to determine the queen's genotype by non-lethal means. The array is now publicly available and we suggest it will be a useful tool in genomic selection and honey bee breeding, as well as for GWAS of different traits, and for population genomic, adaptation and conservation questions.

opencc-zeroOct 2020View details →

Selection signatures in two oldest Russian native cattle breeds revealed using high-density single nucleotide polymorphism analysis

Native cattle breeds can carry specific signatures of selection reflecting their adaptation to the local environmental conditions and response to the breeding strategy used. In this study, we comprehensively analysed high-density single nucleotide polymorphism (SNP) genotypes to characterise the population structure and detect the selection signatures in Russian native Yaroslavl and Kholmogor dairy cattle breeds, which have been little influenced by introgression with transboundary breeds. Fifty-six samples of pedigree-recorded purebred animals, originating from different breeding farms and representing different sire lines, of the two studied breeds were genotyped using a genome-wide bovine genotyping array (Bovine HD BeadChip). Three statistical analyses—calculation of fixation index (FST) for each SNP for the comparison of the pairs of breeds, hapFLK analysis, and estimation of the runs of homozygosity (ROH) islands shared in more than 50% of animals—were combined for detecting the selection signatures in the genome of the studied cattle breeds. We confirmed nine and six known regions under putative selection in the genomes of Yaroslavl and Kholmogor cattle, respectively; the flanking positions of most of these regions were elucidated. Only two of the selected regions (localised on BTA 14 at 24.4–25.1 Mbp and on BTA 16 at 42.5–43.5 Mb) overlapped in Yaroslavl, Kholmogor and Holstein breeds. In addition, we detected three novel selection sweeps in the genome of Yaroslavl (BTA 4 at 4.74–5.36 Mbp, BTA 15 at 17.80–18.77 Mbp, and BTA 17 at 45.59–45.61 Mbp) and Kholmogor breeds (BTA 12 at 82.40–81.69 Mbp, BTA 15 at 16.04–16.62 Mbp, and BTA 18 at 0.19–1.46 Mbp) by using at least two of the above-mentioned methods. We expanded the list of candidate genes associated with the selected genomic regions and performed their functional annotation. We discussed the possible involvement of the identified candidate genes in artificial selection in connection with the origin and development of the breeds. Our findings on the Yaroslavl and Kholmogor breeds obtained using high-density SNP genotyping and three different statistical methods allowed the detection of novel putative genomic regions and candidate genes that might be under selection. These results might be useful for the sustainable development and conservation of these two oldest Russian native cattle breeds.

opencc-zeroDec 2014View details →

Data from: Identifying litchi (Litchi chinensis Sonn.) cultivars and their genetic relationships using single nucleotide polymorphism (SNP) markers

Litchi is an important fruit tree in tropical and subtropical areas of the world. However, there is widespread confusion regarding litchi cultivar nomenclature and detailed information of genetic relationships among litchi germplasm is unclear. In the present study, the potential of single nucleotide polymorphism (SNP) for the identification of 96 representative litchi accessions and their genetic relationships in China was evaluated using 155 SNPs that were evenly spaced across litchi genome. Ninety SNPs with minor allele frequencies above 0.05 and a good genotyping success rate were used for further analysis. A relatively high level of genetic variation was observed among litchi accessions, as quantified by the expected heterozygosity (He = 0.305). The SNP based multilocus matching identified two synonymous groups, 'Heiye' and 'Wuye', and 'Chengtuo' and 'Baitangli 1'. A subset of 14 SNPs was sufficient to distinguish all the non-redundant litchi genotypes, and these SNPs were proven to be highly stable by repeated analyses of a selected group of cultivars. Unweighted pair-group method of arithmetic averages (UPGMA) cluster analysis divided the litchi accessions analyzed into four main groups, which corresponded to the traits of extremely early-maturing, early-maturing, middle-maturing, and late-maturing, indicating that the fruit maturation period should be considered as the primary criterion for litchi taxonomy. Two subpopulations were detected among litchi accessions by STRUCTURE analysis, and accessions with extremely early- and late-maturing traits showed membership coefficients above 0.99 for Cluster 1 and Cluster 2, respectively. Accessions with early- and middle-maturing traits were identified as admixture forms with varying levels of membership shared between the two clusters, indicating their hybrid origin during litchi domestication. The results of this study will benefit litchi germplasm conservation programs and facilitate maximum genetic gains in litchi breeding programs.

Data from: Accuracy of assignment of Atlantic salmon (Salmo salar L.) to rivers and regions in Scotland and northeast England based on single nucleotide polymorphism (SNP) markers.

Understanding the habitat use patterns of migratory fish, such as Atlantic salmon (Salmo salar L.), and the natural and anthropogenic impacts on them, is aided by the ability to identify individuals to their stock of origin. Presented here are the results of an analysis of informative single nucleotide polymorphic (SNP) markers for detecting genetic structuring in Atlantic salmon in Scotland and NE England and their ability to allow accurate genetic stock identification. 3,787 fish from 147 sites covering 27 rivers were screened at 5,568 SNP markers. In order to identify a cost-effective subset of SNPs, they were ranked according to their ability to differentiate between fish from different rivers. A panel of 288 SNPs was used to examine both individual assignments and mixed stock fisheries and eighteen assignment units were defined. The results improved greatly on previously available methods and, for the first time, fish caught in the marine environment can be confidently assigned to geographically coherent units within Scotland and NE England, including individual rivers. As such, this SNP panel has the potential to aid understanding of the various influences acting upon Atlantic salmon on their marine migrations, be they natural environmental variations and/or anthropogenic impacts, such as mixed stock fisheries and interactions with marine power generation installations.

opencc-zeroAug 2019View details →

Data from: Comprehensive evaluation of genetic population structure for anadromous river herring with single nucleotide polymorphism data

Anthropogenic activities are placing increasing pressure on many species, particularly those that rely on more than one ecosystem. River herring (alewife, Alosa pseudoharengus and blueback herring, A. aestivalis collectively) are anadromous fishes that reproduce in rivers and streams of eastern North America and migrate to the western Atlantic Ocean. Here, we use data from single nucleotide polymorphisms (SNPs) to provide a comprehensive analysis of population structure for both species of river herring throughout their native ranges. We sampled river herring spawning runs in rivers from Newfoundland to Florida, examining a total of 108 locations, and genotyping over 8000 fish. We identified geographic population groupings (regional genetic groups) in each species, as well as significant genetic differentiation between most populations and rivers. Strong correlations between geographic and genetic distances (i.e., isolation by distance) were found range-wide for both species, although the patterns were less consistent at smaller spatial scales. River herring are caught as bycatch in fisheries and estimating stock proportions in mixed fishery samples is important for management. We assessed the utility of the SNP datasets as reference baselines for genetic stock identification. Results indicated high accuracy of individual assignment (76–95%) to designated regional genetic groups, and some individual populations, as well as highly accurate estimates of mixing proportions for both species. This study is the first to evaluate genetic structure across the entire geographic range of these species and provides an important foundation for conservation and management planning. The SNP reference datasets will facilitate continued multi-lateral monitoring of bycatch, as well as ecological investigation to provide information about ocean dispersal patterns of these species.

Data from: Development of nuclear microsatellite loci and mitochondrial single nucleotide polymorphisms for the natterjack toad, Bufo (Epidalea) calamita (Bufonidae), using next generation sequencing and Competitive Allele Specific PCR (KASPar)

Amphibians are undergoing a major decline worldwide and the steady increase in the number of threatened species in this particular taxa highlights the need for conservation genetics studies using high-quality molecular markers. The natterjack toad, Bufo (Epidalea) calamita, is a vulnerable pioneering species confined to specialized habitats in Western Europe. To provide efficient and cost-effective genetic resources for conservation biologists, we developed and characterized 22 new nuclear microsatellite markers using next-generation sequencing. We also used sequence data acquired from Sanger sequencing to develop the first mitochondrial markers for KASPar assay genotyping. Genetic polymorphism was then analyzed for 95 toads sampled from 5 populations in France. For polymorphic microsatellite loci, number of alleles and expected heterozygosity ranged from 2 to 14 and from 0.035 to 0.720, respectively. No significant departures from panmixia were observed (mean multilocus F IS = −0.015) and population differentiation was substantial (mean multilocus F ST = 0.222, P < 0.001). From a set of 18 mitochondrial SNPs located in the 16S and D-loop region, we further developed a fast and cost-effective SNP genotyping method based on competitive allele-specific PCR amplification (KASPar). The combination of allelic states for these mitochondrial DNA SNP markers yielded 10 different haplotypes, ranging from 2 to 5 within populations. Populations were highly differentiated (G ST = 0.407, P < 0.001). These new genetic resources will facilitate future parentage, population genetics and phylogeographical studies and will be useful for both evolutionary and conservation concerns, especially for the set-up of management strategies and the definition of distinct evolutionary significant units.

opencc-zeroDec 2013View details →

Data from: A comparison of single nucleotide polymorphism and microsatellite markers for analysis of parentage and kinship in a cooperatively breeding bird

The development of genetic markers has revolutionized molecular studies within and among populations. Although poly-allelic microsatellites are the most commonly used genetic marker for within-population studies of free-living animals, biallelic single nucleotide polymorphisms, or SNPs, have also emerged as a viable option for use in nonmodel systems. We describe a robust method of SNP discovery from the transcriptome of a nonmodel organism that resulted in more than 99% of the markers working successfully during genotyping. We then compare the use of 102 novel SNPs with 15 previously developed microsatellites for studies of parentage and kinship in cooperatively breeding superb starlings (Lamprotornis superbus) that live in highly kin-structured groups. For 95% of the offspring surveyed, SNPs and microsatellites identified the same genetic father, but only when behavioural information about the likely parents at a nest was included to aid in assignment. Moreover, when such behavioural information was available, the number of SNPs necessary for successful parentage assignment was reduced by half. However, in a few cases where candidate fathers were highly related, SNPs did a better job at assigning fathers than microsatellites. Despite high variation between individual pairwise relatedness values, microsatellites and SNPs performed equally well in kinship analyses. This study is the first to compare SNPs and microsatellites for analyses of parentage and relatedness in a species that lives in groups with a complex social and kin structure. It should also prove informative for those interested in developing SNP loci from transcriptome data when published genomes are unavailable.

opencc-zeroDec 2012View details →

Data from: Signatures of selection in the Iberian honey bee (Apis mellifera iberiensis) revealed by a genome scan analysis of single nucleotide polymorphisms

Understanding the genetic mechanisms of adaptive population divergence is one of the most fundamental endeavours in evolutionary biology and is becoming increasingly important as it will allow predictions about how organisms will respond to global environmental crisis. This is particularly important for the honey bee, a species of unquestionable ecological and economical importance that has been exposed to increasing human-mediated selection pressures. Here, we conducted a single nucleotide polymorphism (SNP)-based genome scan in honey bees collected across an environmental gradient in Iberia and used four FST-based outlier tests to identify genomic regions exhibiting signatures of selection. Additionally, we analysed associations between genetic and environmental data for the identification of factors that might be correlated or act as selective pressures. With these approaches, 4.4% (17 of 383) of outlier loci were cross-validated by four FST-based methods, and 8.9% (34 of 383) were cross-validated by at least three methods. Of the 34 outliers, 15 were found to be strongly associated with one or more environmental variables. Further support for selection, provided by functional genomic information, was particularly compelling for SNP outliers mapped to different genes putatively involved in the same function such as vision, xenobiotic detoxification and innate immune response. This study enabled a more rigorous consideration of selection as the underlying cause of diversity patterns in Iberian honey bees, representing an important first step towards the identification of polymorphisms implicated in local adaptation and possibly in response to recent human-mediated environmental changes.

opencc-zeroDec 2012View details →

Data from: Concholepas concholepas Ferritin H-like subunit (CcFer): molecular characterization and single nucleotide polymorphism associated to innate immune response

Ferritin has been shown as the principal protein of iron storage and iron detoxification, playing a pivotal role for the cellular homeostasis in living organisms. However, recent studies in marine invertebrates have suggested its association with innate immune system. In the present study, one Ferritin subunit was identified from the gastropod Concholepas concholepas (CcFer), which was fully characterized by Rapid Amplification of cDNA Ends technique. Simultaneously, a challenge test was performed to evaluate the immune response against Vibrio anguillarum. The full length of cDNA Ccfer was 1,030 bp, containing 513 bp of open reading frame that encodes 170 amino acid peptides, which was similar to the Ferritin-H subunit described in vertebrates. Untranslated Regions (UTRs) were identified with a 5'UTR of 244 bp that contains iron responsive element (IRE), and a 3'UTR of 273 pb. The predicted molecular mass of deduced amino acid of CcFer was 19.66 kDa and isoelectric point of 4.92. Gene transcription analysis revealed that CcFer increases against infections with V. anguillarum, showing a peak expression at 6 hours post-infection. Moreover, a single nucleotide polymorphism was detected at -64 downstream 5'UTR sequence (SNP-64). Quantitative real time analysis showed that homozygous mutant allele (TT) was significantly associated with higher expression levels of the challenged group compared to wild (CC) and heterozygous (CT) variants. Our findings suggest that CcFer is associated to innate immune response in C. concholepas and that the presence of SNPs may involve differential transcriptional expression of CcFer.

Data from: Geographic structure in the Southern Ocean circumpolar brittle star Ophionotus victoriae (Ophiuridae) revealed from mtDNA and single nucleotide polymorphism data

Marine systems have traditionally been thought of as "open" with few barriers to gene flow. In particular, many marine organisms in the Southern Ocean purportedly possess circumpolar distributions that have rarely been well verified. Here, we use the highly abundant and endemic Southern Ocean brittle star Ophionotus victoriae to examine genetic structure and determine whether barriers to gene flow have existed around the Antarctic continent. Ophionotus victoriae possesses feeding planktotrophic larvae with presumed high dispersal capability, but a previous study revealed genetic structure along the Antarctic Peninsula. To test the extent of genetic differentiation within O. victoriae, we sampled from the Ross Sea through the eastern Weddell Sea. Whereas two mitochondrial DNA markers (16S rDNA and COI) were employed to allow comparison to earlier work, a 2b-RAD single-nucleotide polymorphism (SNP) approach allowed sampling of loci across the genome. Mitochondrial data from 414 individuals suggested three major lineages, but 2b-RAD data generated 1,999 biallelic loci that identified four geographically distinct groups from 89 samples. Given the greater resolution by SNP data, O. victoriae can be divided into geographically distinct populations likely representing multiple species. Specific historical scenarios that explain current population structure were examined with approximate Bayesian computation (ABC) analyses. Although the Bransfield Strait region shows high diversity possibly due to mixing, our results suggest that within the recent past, dispersal processes due to strong currents such as the Antarctic Circumpolar Current have not overcome genetic subdivision presumably due to historical isolation, questioning the idea of large open circumpolar populations in the Southern Ocean.

Data from: Genome-wide single nucleotide polymorphism (SNP) identification and characterization in a non-model organism, the African buffalo (Syncerus caffer), using next generation sequencing

This study aimed to develop a set of SNP markers with high resolution and accuracy within the African buffalo. Such a set can be used, among others, to depict subtle population genetic structure for a better understanding of buffalo population dynamics. In total, 18.5 million DNA sequences of 76 bp were generated by next generation sequencing on an Illumina Genome Analyzer II from a reduced representation library using DNA from a panel of 13 African buffalo representative of the four subspecies. We identified 2534 SNPs with high confidence within the panel by aligning the short sequences to the cattle genome (Bos taurus). The average sequencing depth of the complete aligned set of reads was estimated at 5x, and at 13x when only considering the final set of putative SNPs that passed the filtering criterion. Our set of SNPs was validated by PCR amplification and Sanger sequencing of 15 SNPs. Of these 15 SNPs, 14 amplified successfully and 13 were shown to be polymorphic (success rate: 87%). The fidelity of the identified set of SNPs and potential future applications are finally discussed.

opencc-zeroDec 2009View details →

Data from: Multiplex preamplification PCR and microsatellite validation allows accurate single nucleotide polymorphism (SNP) genotyping of historical fish scales

Incorporating historical tissues into the study of ecological, conservation, and management questions can broaden the scope of population genetic research by enhancing our understanding of evolutionary processes and anthropogenic influences on natural populations. Genotyping historical and low-quality samples has been plagued by challenges associated with low amounts of template DNA and the potential for preexisting DNA contamination among samples. We describe a two-step process designed to (i) accurately genotype large numbers of historical low-quality scale samples in a high-throughput format and (ii) screen samples for preexisting DNA contamination. First, we describe how an efficient multiplex preamplification PCR of 45 single nucleotide polymorphisms (SNPs) can generate highly accurate genotypes with low failure and error rates in subsequent SNP genotyping reactions of individual historical scales from sockeye salmon (Oncorhynchus nerka). Second, we demonstrate how the method can be modified for the amplification of microsatellite loci to detect preexisting DNA contamination. A total of 760 individual historical scale and 182 contemporary fin clip samples were genotyped and screened for contamination. Genotyping failure and error rates were exceedingly low and similar for both historical and contemporary samples. Preexisting contamination in 21% of the historical samples was successfully identified by screening the amplified microsatellite loci. The potential for automation, low failure and error rates, and ability to multiplex both the preamplification and subsequent genotyping reactions combine to make the protocol ideally suited for efficiently genotyping large numbers of potentially contaminated low-quality sources of DNA.

opencc-by-4.0Sep 2022View details →

Western redcedar single nucleotide polymorphism (SNP) genotyping data for genomic selection and population genetics

Western redcedar (Thuja plicata) Single Nucleotide Polymorphism (SNP) data in Variant Call Format (VCF) for genomic selection training and target populations, genomic selection parents, and self-fertilized (selfing) lines, comprising 4,833 trees. Targeted sequencing-based genotyping was done by Capture-Seq methodology at Rapid Genomics (Neves est al. 2013). A set of 57,000 probes as designed for initial marker discovery, from which a panel of 20,858 probes was selected for genotyping. A set of transcriptomes (Shalev et al. 2018) (PRJNA704616) was aligned to the reference genome to identify SNPs. Candidate probes (120 nt) were initially designed in silico and 57,000 selected by removing candidates with poor base composition for hybridization (GC content <0.2 and >0.6, high G content >0.2 and long homopolymers >7), followed by removing probes aligning to more than one position on the reference genome (≥90% identity and length). The 57,000 probes represent 14,517 scaffolds (average 3.9 probes/scaffold), with 37,275 targeting at least one SNP and 19,725 mapping to intergenic regions not containing pre-identified SNPs. A set of 128 individuals were selected to validate the 57,000 probe panel and associated polymorphisms. Genomic DNA (0.5 ug) was fragmented (mean size 300 bp), followed by repair of ends, phosphorylation, adenylation, ligation of Illumina compatible adapters containing 8bp indexes and 5’ T-overhang, and 10 cycles PCR amplification with universal primers to produce sequencing-ready libraries. Libraries were quantified using PicoGreen. Libraries from 16 samples were pooled, hybridized to the 120 nt RNA probes following Agilent’s SureSelect Target Enrichment System (Agilent Technologies) and sequenced on an Illumina HiSeq X machine with paired-end 150bp cycle for an average sequencing depth per sample of 15X. Sequence data were aligned to the reference genome with BWA-MEM (http://arxiv.org/abs/1303.3997) and sets of four samples were combined to increase sequencing depth for identifying markers. Putative SNPs were identified using Freebayes (http://arxiv.org/abs/1207.3907) in 150bp on either side of the 57,000 probes and filtered probes that had more than 17 SNPs per 420 bp target region (150bp + 120bp + 150bp). The sequencing depth of the probes was used to select the final set of 20,885 probes, removing probes on both sides of the distribution (low and high sequencing depth), for Capture-Seq on the remainder of the samples.

opennotspecifiedNov 2018View details →

Fig. 2 in Inferring Ancestry and Divergence Events in a Forest Pest Using Low-Density Single-Nucleotide Polymorphisms

Fig. 2. Population tree inferred by TreeMix using all 42 sampling sites across the mountain pine beetle range. Terminal branches are labeled using locality information (see Supp Fig. 1 [online only] for further detail) and migration arrows are colored according to migration weight.

opennotspecifiedNov 2018View details →

Fig. 3. Scenario 9 in Inferring Ancestry and Divergence Events in a Forest Pest Using Low-Density Single-Nucleotide Polymorphisms

Fig. 3. Scenario 9 was identified as the 'best' from 11 competing phylogeographic scenarios. This scenario represents an east-to-west colonization route with stable population sizes in which cluster 4 is derived from clusters 1 and 3 through admixture. Terminal branch labels are consistent with the five STRUCTURE clusters identified (Fig. 1). T = time expressed as number of generations assuming one generation per year; R = inferred migration rate.

opennotspecifiedNov 2018View details →

Fig. 1 in Inferring Ancestry and Divergence Events in a Forest Pest Using Low-Density Single-Nucleotide Polymorphisms

Fig. 1. Map of mountain pine beetle sites throughout western North America. Each site is represented by a pie chart depicting the average assignment (Q values) of individuals to one of five STRUCTURE clusters (K = 5).

opencc-zeroDec 2010View details →

Data from: Single nucleotide polymorphisms across a species' range: implications for conservation studies of Pacific salmon

Studies of the oceanic and near-shore distributions of Pacific salmon, whose migrations typically span thousands of kilometers, have become increasingly valuable in the presence of climate change, increasing hatchery production, and potentially high rates of bycatch in offshore fisheries. Genetics data offer considerable insights into both the migratory routes as well as the evolutionary histories of the species. However, these types of studies require extensive datasets from spawning populations originating from across the species? range. Single nucleotide polymorphisms (SNPs) have been particularly amenable for multi-national applications because they are easily shared, require little inter-laboratory standardization, and can be assayed through increasingly efficient technologies. Here we discuss the development of a dataset for 114 populations of chum salmon through a collaboration among North American and Asian researchers, termed PacSNP. PacSNP is focused on developing the database and applying it to problems of international interest. A dataset spanning the entire range of species provides a unique opportunity to examine patterns of variability, and we review issues associated with SNP development. We found evidence of ascertainment bias within the dataset, variable linkage relationships between SNPs associated with ancestral groupings, and outlier loci with alleles associated with latitude.

opencc-zeroDec 2014View details →

Data from: Single-nucleotide polymorphism discovery and validation in high-density SNP array for genetic analysis in European white oaks

An Illumina Infinium SNP genotyping array was constructed for European white oaks. Six individuals of Quercus petraea and Q. robur were considered for SNP discovery using both previously obtained Sanger sequences across 676 gene regions (1371 in vitro SNPs) and Roche 454 technology sequences from 5112 contigs (6542 putative in silico SNPs). The 7913 SNPs were genotyped across the six parental individuals, full-sib progenies (one within each species and two interspecific crosses between Q. petraea and Q. robur) and three natural populations from south-western France that included two additional interfertile white oak species (Q. pubescens and Q. pyrenaica). The genotyping success rate in mapping populations was 80.4% overall and 72.4% for polymorphic SNPs. In natural populations, these figures were lower (54.8% and 51.9%, respectively). Illumina genotype clusters with compression (shift of clusters on the normalized x-axis) were detected in ~25% of the successfully genotyped SNPs and may be due to the presence of paralogues. Compressed clusters were significantly more frequent for SNPs showing a priori incorrect Illumina genotypes, suggesting that they should be considered with caution or discarded. Altogether, these results show a high experimental error rate for the Infinium array (between 15% and 20% of SNPs potentially unreliable and 10% when excluding all compressed clusters), and recommendations are proposed when applying this type of high-throughput technique. Finally, results on diversity levels and shared polymorphisms across targeted white oaks and more distant species of the Quercus genus are discussed, and perspectives for future comparative studies are proposed.