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28 records · Page 2Linked to original sources

Beckwith-Wiedemann spectrum exhibiting a 46,XY karyotype caused by genome-wide paternal uniparental heterodisomy: a case report.

BACKGROUNDS: Patients with genome-wide paternal uniparental disomy (GWpUPD) usually exhibit clinical features of Beckwith-Wiedemann syndrome (BWS) and a 46,XX karyotype, with all chromosomes showing isodisomy. To date, male patients with GWpUPD and a complete 46,XY karyotype, specifically involving heterodisomy, have not been described. RESULTS: We report a male infant exhibiting classical BWS clinical features. DNA methylation analyses showed paternal-specific methylation across multiple imprinted loci, suggesting GWpUPD. Genetic analysis of autosomes and sex chromosomes indicated two distinct paternal genomes in peripheral blood leukocytes, whereas a normal biparental genome was detected in other tissues under chimeric conditions. These findings indicated that the patient had genome-wide paternal uniparental heterodisomy (GWpUPhD). The SNP array revealed the presence of one copy of the X chromosome and one copy of the Y chromosome, the patient is a chimera composed of 46,XY biparental cells (with maternal X) and 46,XY GWpUPhD cells (with paternal X). CONCLUSIONS: This is the first report of a male patient with a GWpUPhD chimera. We propose a potential mechanism of GWpUPhD formation. Our findings expand the molecular spectrum of GWpUPD and provide valuable insights into its pathogenesis in chimeric conditions. Furthermore, the potential for clinical manifestations unique to 46,XY heterodisomy warrants careful long-term follow-up.

Humans

Integration of Morphological and Genome-Wide SNP Data Reveals Regional Diversity in Thai Swamp Buffalo.

Thai swamp buffalo (Bubalus bubalis) are valuable animal genetic resources, but their regional diversity remains incompletely characterized. Morphological records were obtained from 799 buffaloes, and 474 individuals were genotyped using the 90K Axiom® Buffalo SNP Genotyping Array (Thermo Fisher Scientific, Applied Biosystems™, Santa Clara, CA, USA). Qualitative traits included coat color, horn shape, chevron pattern, and hair-whorl distribution, while quantitative characterization covered 30 body measurements. After excluding missing traits, 30 traits adjusted for sex, age, province, and farm from 768 animals were used for morphology-based analyses, which identified regional phenotypic differences but also substantial overlap, consistent with the influence of feeding, management, environment, and local selection on body conformation. Genome-wide SNP analyses indicated a broadly shared genetic background with detectable regional structure, and runs of homozygosity revealed regional differences in genomic autozygosity. The Lower South showed a comparatively strong recurrent-ROH pattern, whereas inference for the Upper South requires caution because of its small genomic sample. Overall, integrating morphology and genome-wide SNP data improves regional characterization, but data-dependent statistics, population-structure estimates, and conservation implications should be interpreted while regarding small sampling and unbalanced data.

Bubalus bubalis

Pedigree-assisted genotype imputation enables cost-effective genomic prediction in Penaeus vannamei.

Genomic selection in Penaeus vannamei has long been constrained by the high cost of dense genotyping. To address this limitation, we evaluated genotype imputation from a low-density 1 K panel to a medium-density 55 K panel of the "Yellow Sea Array No. 1" and examined its impact on genomic prediction for harvest body weight in P. vannamei. A four-generation pedigree including 30 great-grandparents, 39 grandparents, 100 parents, and 608 offspring was genotyped using the 55 K panel. A two-step experimental design was implemented to (i) assess the performance of different imputation algorithms under reference population scenarios with varying proportions of siblings, and (ii) compare six alternative reference population structures incorporating parents, ancestors, and siblings. Genotype imputation using the pedigree-based method FImpute v3.0 consistently achieved higher accuracy than the population-based method Beagle v5.5. Using this pedigree-assisted approach, imputation accuracy increased from 0.73 when only parental genotypes were used to 0.84 with the inclusion of 10% siblings, and subsequently plateaued at 0.87-0.90 when sibling representation reached 20%. Across the six reference population structures, imputation accuracy was primarily driven by the availability of parental genotypes, ranging from 0.50 to 0.56 in the absence of parents to 0.88-0.89 when both parents and ancestral generations were included. Accuracy remained high when both parents were available (0.84-0.87 with siblings; 0.73 without siblings) but declined substantially when only one parent was genotyped (0.65-0.68). Imputation accuracy was positively associated with both minor allele frequency (MAF) and linkage disequilibrium (max r2LD), with LD exerting the stronger influence. Heritability estimates derived from imputed 55 K genotypes were highly consistent with those obtained from the original 55 K data (0.39 ± 0.14 vs. 0.41 ± 0.14), indicating that genotype imputation did not compromise variance component estimation. In predictive ability analyses, pedigree-based BLUP (PBLUP) achieved higher predictive ability than genomic BLUP (GBLUP) based on the 1 K panel, with predictive abilities of 0.42-0.44 for PBLUP compared with 0.34-0.35 for GBLUP. Using imputed genotypes for genomic prediction further improved predictive ability relative to the true 1 K panel, yielding values ranging from 0.35 to 0.47. Notably, when parental genotypes were included in the reference population, GBLUP based on imputed genotypes surpassed the predictive ability of PBLUP and approached that achieved with the original 55 K genotypes (0.45-0.47). Collectively, these results provide the first empirical evidence that low- to medium-density genotype imputation, combined with pedigree information, can effectively support genomic prediction in P. vannamei. This study establishes a cost-efficient and scalable framework for implementing genomic selection in P. vannamei and provides a practical reference for the application of genomic selection in other aquaculture species with constrained breeding budgets.

Animals

First genomic insights into the introgression of almond PPV-Marcus resistance into peach.

AIM: Sharka, caused by Plum pox virus (PPV), is one of the most damaging viral diseases of stone fruit crops, with peach among the most susceptible cultivated Prunus species. Almond is a promising source of resistance, but its genetic architecture and expression in a peach genetic background remain largely unknown. This study aimed to construct parental genetic linkage maps and identify genomic regions associated with PPV response in almond × peach interspecific populations. METHODS: Progenies derived from the almond cultivars 'Del Cid', 'Garrigues', and 'Mono' were evaluated by RT-PCR after graft inoculation with the PPV-Marcus (PPV-M) strain over consecutive infection cycles. Phenotypic data were summarized for each genotype using best linear unbiased estimates (BLUEs). High-density SNP almond and peach arrays were used to construct parental maps for 'Garrigues' and 'Mono' and perform quantitative trait locus (QTL) analysis. RESULTS: Phenotypic variation was observed among and within families. 'Del Cid'-derived progenies showed the greatest resistance, 'Garrigues'-derived progenies displayed intermediate responses, and 'Mono'-derived progenies showed greater susceptibility and variability. The parental maps covered 546.69 cM in 'Mono' and 521.72 cM in 'Garrigues', with average intervals of 0.61 and 1.26 cM per unique marker position, respectively, and showed strong collinearity with the reference genome. QTL associated with PPV-M response were detected on linkage groups (LG) 1 and 6 in 'Garrigues' and LG2 in 'Mono'. The main QTL in 'Garrigues' peaked near 22.39 Mb on LG1, whereas the 'Mono' QTL was located at 22.27-22.62 Mb on LG2; a weaker QTL was detected near 25.38 Mb on LG6 in 'Garrigues'. The results support a quantitative and genetic-background-dependent architecture of PPV resistance. CONCLUSION: This study provides the first evidence of genomic regions associated with PPV-Marcus response in almond × peach populations. The detected QTLs provide an initial basis to support the introgression of almond-derived resistance into peach breeding material.

Prunus

SNP genotyping in Pseudotsuga menziesii and Pinus radiata using targeted genotyping-by-sequencing (GBS): improved Bayesian SNP calling using a beta-binomial distribution and other optimized input parameters.

BACKGROUND: Single-nucleotide polymorphism markers (SNPs) have important applications in gene conservation, breeding, and fundamental genetics research. Our long-term goal is to develop routine approaches for SNP genotyping in forest trees. Ideally, these approaches would be inexpensive, able to accommodate a wide range of samples and SNPs, available through commercial providers, and produce high-quality SNP data. RESULTS: Using targeted genotyping-by-sequencing (GBS), we developed SNP assays for two highly heterozygous tree species, Douglas-fir (Pseudotsuga menziesii) and radiata pine (Pinus radiata). Using Douglas-fir haploid and diploid data, we optimized Bayesian SNP calling by testing four input parameters: (1) allele and genotype prior probabilities, (2) Rho, the beta-binomial dispersion parameter, (3) estimated read error (BayesReadError), and (4) the logPO cutoff used to filter low confidence SNP calls. logPO is the Bayesian posterior odds ratio for a called SNP. Compared to assuming a binomial distribution of read counts (Rho = 0), the beta-binomial distribution (Rho = 0.33) substantially reduced call error and heterozygote undercalling. Compared to the other Bayesian parameters, genotype priors had little effect on genotyping success. For Douglas-fir, we tested 5,360 SNP assays, and then studied the performance of the best 4,000. For radiata pine, we tested 6,000 SNP assays, and then studied the performance of the best 4,570. In Douglas-fir and radiata pine, our Bayesian approach resulted in median call rates of 95% to 98% for the top-ranked SNPs, with an estimated call error of 1.60% for known homozygous genotypes and 2.27% for known heterozygotes. In radiata pine, median and mean call rates were above 91% for GBS and SNP genotyping using an Axiom fixed genotyping array. Additionally, the median correspondence between the GBS and Axiom genotypes was about 98% overall (mean 96%). CONCLUSIONS: By optimizing Bayesian SNP calling, selecting the best 4-5 K SNPs, and excluding samples with low DNA amounts, we substantially reduced call error and heterozygote undercalling, resulting in SNP genotypes that were nearly identical to genotypes obtained using the Axiom array. Furthermore, genotyping performance should increase even further if our SNP rankings were used to develop less complex probe pools that target fewer SNPs.

Pinus

Genome-wide association study and KASP development for growth and leaf traits in Populus deltoides.

BACKGROUND: Populus deltoides is a valuable timber species of considerable importance in the study of forest genetic breeding. However, its genetic improvement continues to rely predominantly on conventional selection and hybridization strategies hampered by long breeding cycles and limited efficiency. RESULTS: A total of 209 P. deltoides accessions were genotyped using a 60K SNP (Single nucleotide polymorphism) liquid array. Following quality control, 46,031 high-quality SNPs were screened and analyzed alongside 15 phenotypic traits in a genome-wide association study (GWAS), which identified 219 SNPs significantly associated with the traits. After further screening and annotation, a final set of 57 target SNPs and 77 candidate genes was obtained. Using kompetitive allele-specific PCR (KASP) assays, we successfully developed 48 polymorphic KASP markers. Of these, 25 markers exhibited significant phenotypic differences (p&#x2009;<&#x2009;0.05) across genotype groups. CONCLUSIONS: These 25 KASP markers can serve as reliable and practical tools for phenotype-assisted selection, providing efficient molecular resources for accelerating genetic improvement and marker-assisted breeding in poplar.

Populus

Optimizing genetic ancestry adjustment in DNA methylation studies: a comparative analysis of approaches.

BACKGROUND: Genetic ancestry is an important factor to account for in DNA methylation studies because genetic variation influences DNA methylation patterns. One approach uses principal components (PCs) calculated from CpG sites that overlap with common SNPs to adjust for ancestry when genotyping data is not available. However, this method does not remove technical and biological variations, such as sex and age, prior to calculating the PCs. The first PC is therefore often associated with factors other than ancestry. METHODS: We developed and adapted the adapted EpiAnceR+&#x2009;approach, which includes (1) residualizing the CpG data overlapping with common SNPs for control probe PCs, sex, age, and cell type proportions to remove the effects of technical and biological factors, and (2) integrating the residualized data with genotype calls from the SNP probes (commonly referred to as rs probes) present on the arrays, before calculating PCs and evaluated the clustering ability and relationship to genetic ancestry. RESULTS: The PCs generated by EpiAnceR+&#x2009;led to improved clustering for repeated samples from the same individual and stronger associations with genetic ancestry groups predicted from genotype information compared to the original approach. EpiAnceR+&#x2009;also outperformed the use of DNA methylation PCs or surrogate variables for ancestry adjustment. CONCLUSIONS: We show that the EpiAnceR+&#x2009;approach improves the adjustment for genetic ancestry in DNA methylation studies. EpiAnceR+&#x2009;can be integrated into existing R pipelines for commercial methylation arrays, such as 450&#xa0;K, EPIC v1, and EPIC v2. The code is available on GitHub ( https://github.com/KiraHoeffler/EpiAnceR ).

DNA Methylation

Development of a 10K breeder-friendly SNP chip for faba bean.

INTRODUCTION: Faba bean breeding and genomics have seen steady progress in recent years, supported by genome sequences and high-density genotyping platforms. These tools have been valuable for trait mapping, diversity assessment, and genomic research, but they have limited routine use in breeding programs due to their relatively high cost. Recent progress in establishing an optimized, cost-efficient genotyping-by-sequencing protocol tailored to the large and complex faba bean genome has created the foundation for a more accessible genotyping solution. METHODS: Using this approach, we explored the genetic diversity of faba bean germplasm from various panels, providing a comprehensive representation of the crop's genetic landscape. From this dataset, we identified and selected a high-quality set of informative SNP markers that are evenly distributed across the genome. Building on these resources, we designed a breeder-friendly 10K SNP chip. RESULTS: The 10K SNP chip delivers high accuracy, broad genomic coverage, and affordability. The chip was validated across diverse germplasm panels, demonstrating strong clustering performance, high reproducibility, and applicability to breeding-relevant germplasm. DISCUSSION: This platform offers a cost-effective alternative to higher-density arrays, enabling its integration into genomic selection, marker-assisted breeding, and diversity monitoring, ultimately supporting accelerated genetic gain and the delivery of improved varieties to farmers.

SNP chip

Sequencing the orthologs of human autosomal forensic short tandem repeats provides individual- and species-level identification in African great apes.

BACKGROUND: Great apes are a global conservation concern, with anthropogenic pressures threatening their survival. Genetic analysis can be used to assess the effects of reduced population sizes and the effectiveness of conservation measures. In humans, autosomal short tandem repeats (aSTRs) are widely used in population genetics and for forensic individual identification and kinship testing. Traditionally, genotyping is length-based via capillary electrophoresis (CE), but there is an increasing move to direct analysis by massively parallel sequencing (MPS). An example is the ForenSeq DNA Signature Prep Kit, which amplifies multiple loci including 27 aSTRs, prior to sequencing via Illumina technology. Here we assess the applicability of this human-based kit in African great apes. We ask whether cross-species genotyping of the orthologs of these loci can provide both individual and (sub)species identification. RESULTS: The ForenSeq kit was used to amplify and sequence aSTRs in 52 individuals (14 chimpanzees; 4 bonobos; 16 western lowland, 6 eastern lowland, and 12 mountain gorillas). The orthologs of 24/27 human aSTRs amplified across species, and a core set of thirteen loci could be genotyped in all individuals. Genotypes were individually and (sub)species identifying. Both allelic diversity and the power to discriminate (sub)species were greater when considering STR sequences rather than allele lengths. Comparing human and African great-ape STR sequences with an orangutan outgroup showed general conservation of repeat types and allele size ranges. Variation in repeat array structures and a weak relationship with the known phylogeny suggests stochastic origins of mutations giving rise to diverse imperfect repeat arrays. Interruptions within long repeat arrays in African great apes do not appear to reduce allelic diversity. CONCLUSIONS: Orthologs of most human aSTRs in the ForenSeq DNA Signature Prep Kit can be analysed in African great apes. Primer redesign would reduce observed variability in amplification across some loci. MPS of the orthologs of human loci provides better resolution for both individual and (sub)species identification in great apes than standard CE-based approaches, and has the further advantage that there is no need to limit the number and size ranges of analysed loci.

Animals

Common genetic variants associated with urinary phthalate levels in children: A genome-wide study.

INTRODUCTION: Phthalates, or dieters of phthalic acid, are a ubiquitous type of plasticizer used in a variety of common consumer and industrial products. They act as endocrine disruptors and are associated with increased risk for several diseases. Once in the body, phthalates are metabolized through partially known mechanisms, involving phase I and phase II enzymes. OBJECTIVE: In this study we aimed to identify common single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) associated with the metabolism of phthalate compounds in children through genome-wide association studies (GWAS). METHODS: The study used data from 1,044 children with European ancestry from the Human Early Life Exposome (HELIX) cohort. Ten phthalate metabolites were assessed in a two-void pooled urine collected at the mean age of 8&#xa0;years. Six ratios between secondary and primary phthalate metabolites were calculated. Genome-wide genotyping was done with the Infinium Global Screening Array (GSA) and imputation with the Haplotype Reference Consortium (HRC) panel. PennCNV was used to estimate copy number variants (CNVs) and CNVRanger to identify consensus regions. GWAS of SNPs and CNVs were conducted using PLINK and SNPassoc, respectively. Subsequently, functional annotation of suggestive SNPs (p-value&#xa0;<&#xa0;1E-05) was done with the FUMA web-tool. RESULTS: We identified four genome-wide significant (p-value&#xa0;<&#xa0;5E-08) loci at chromosome (chr) 3 (FECHP1 for oxo-MiNP_oh-MiNP ratio), chr6 (SLC17A1 for MECPP_MEHHP ratio), chr9 (RAPGEF1 for MBzP), and chr10 (CYP2C9 for MECPP_MEHHP ratio). Moreover, 115 additional loci were found at suggestive significance (p-value&#xa0;<&#xa0;1E-05). Two CNVs located at chr11 (MRGPRX1 for oh-MiNP and SLC35F2 for MEP) were also identified. Functional annotation pointed to genes involved in phase I and phase II detoxification, molecular transfer across membranes, and renal excretion. CONCLUSION: Through genome-wide screenings we identified known and novel loci implicated in phthalate metabolism in children. Genes annotated to these loci participate in detoxification, transmembrane transfer, and renal excretion.

Humans