Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SNP analysis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2002

Genome complexity reduction for SNP genotyping analysis.

Efficient single nucleotide polymorphism (SNP) genotyping methods are necessary to accomplish many current gene discovery goals. A crucial element in large-scale SNP genotyping is the number of individual biochemical reactions that must be performed. An efficient method that can be used to simultaneously amplify a set of genetic loci across a genome with high reliability can provide a valuable tool for large-scale SNP genotyping studies. In this paper we describe and characterize a method that addresses this goal. We have developed a strategy for reducing genome complexity by using degenerate oligonucleotide primer (DOP)-PCR and applied this strategy to SNP genotyping in three complex eukaryotic genomes; human, mouse, and Arabidopsis thaliana. Using a single DOP-PCR primer, SNP loci spread throughout a genome can be amplified and accurately genotyped directly from a DOP-PCR product mixture. DOP-PCRs are extremely reproducible. The DOP-PCR method is transferable to many species of interest. Finally, we describe an in silico approach that can effectively predict the SNP loci amplified in a given DOP-PCR, permitting the design of an efficient set of reactions for large-scale, genome-wide SNP studies.

Animals↗
PubMed2007

A strong genetic determinant of hyperoxia-related retinal degeneration on mouse chromosome 6.

PURPOSE: Hyperoxia-related retinal degeneration (HRRD) is a model system in the mouse in which elevated oxygen levels are used to induce retinal degeneration. The hypothesis for the present study was that strain differences in HRRD susceptibility are due to allelic variants of one or more genes in the mouse genome whose human orthologues should be important targets for research and drug development. METHODS: C57BL/6J, A/J, or B.A-Chr6 mice were exposed to 75% oxygen (hyperoxia) or room air for 14 days. After death, one eye was fixed and processed for outer nuclear layer (ONL) thickness measurements. The retina and RPE/choroid were separately dissected from the fellow eye and processed for microarray analysis. Single nucleotide polymorphism (SNP) analysis for transcribed sequences from the C57BL/6J and A/J genomes was conducted using the NIH genome site. RESULTS: C57BL/6J mice developed a significant retinal degeneration in the inferior hemisphere after 14 days of hyperoxia. Under identical conditions, A/J mice exhibited only minor changes. A significant genetic effect was located on chromosome 6. SNP analysis of known transcribed sequences on chromosome 6 combined with microarray expression analysis yielded 33 candidate genes. CONCLUSIONS: A significant genetic effect of susceptibility to HRRD is located on chromosome 6. In silico analysis of transcribed sequences results in a fairly small number of candidate genes.

Animals↗
PubMed2006

FASTSNP: an always up-to-date and extendable service for SNP function analysis and prioritization.

Single nucleotide polymorphism (SNP) prioritization based on the phenotypic risk is essential for association studies. Assessment of the risk requires access to a variety of heterogeneous biological databases and analytical tools. FASTSNP (function analysis and selection tool for single nucleotide polymorphisms) is a web server that allows users to efficiently identify and prioritize high-risk SNPs according to their phenotypic risks and putative functional effects. A unique feature of FASTSNP is that the functional effect information used for SNP prioritization is always up-to-date, because FASTSNP extracts the information from 11 external web servers at query time using a team of web wrapper agents. Moreover, FASTSNP is extendable by simply deploying more Web wrapper agents. To validate the results of our prioritization, we analyzed 1569 SNPs from the SNP500Cancer database. The results show that SNPs with a high predicted risk exhibit low allele frequencies for the minor alleles, consistent with a well-known finding that a strong selective pressure exists for functional polymorphisms. We have been using FASTSNP for 2 years and FASTSNP enables us to discover a novel promoter polymorphism. FASTSNP is available at http://fastsnp.ibms.sinica.edu.tw.

Gene Frequency↗
PubMed2005

New approaches for genotyping paraffin wax embedded breast tissue from patients with cancer: the Iowa women's health study.

BACKGROUND: The use of paraffin wax embedded tissue samples as a source of DNA for genotype analysis has been limited because of difficulties in DNA extraction and single nucleotide polymorphism (SNP) analysis. AIMS: To test the feasibility of applying the combination of a commonly used DNA isolation procedure, PureGene, and a high throughput SNP analysis method, the polymerase chain reaction (PCR)-INVADER assay, to genotype several types of paraffin wax embedded breast tissues. METHODS: Twenty formalin fixed, paraffin wax blocks were obtained from five participants in the Iowa women's health study. Each participant provided several types of tissue including normal lymph node, normal nipple/areola tissue, inflammatory/fibrotic breast tissue, or normal breast tissue, and tumour tissue. RESULTS: Good quality DNA (260/280 ratio >1.6) was obtained from all tissues. Normal lymph nodes yielded the largest amount of DNA (97.1 mug). DNA obtained from the samples was tested for a germline C1183T polymorphism in the MnSOD gene by three methods-PCR-RFLP (restriction fragment length polymorphism), INVADER assay, and PCR-INVADER assay. Of the 20 samples, PCR-RFLP genotyped 16, the PCR-INVADER assay 18, and the INVADER assay two. This methodology was then used to analyse five additional genotypes and confirmed the general applicability of the method. CONCLUSIONS: This study demonstrated the feasibility of (1) using several paraffin wax embedded breast tissues as a source of DNA for germline genetic analysis, with lymph nodes providing the highest yield, and (2) using the combination of a common extraction method with a high throughput SNP analysis method, the PCR-INVADER assay.

Breast Neoplasms↗
PubMed2005

Loss of heterozygosity testing using real-time PCR analysis of single nucleotide polymorphisms.

PURPOSE: Colon cancer is a genetic disease, caused by mutations in different oncogenes and tumor-suppressor genes. The aim of this study is to evaluate the usefulness of real-time PCR SNP analysis as a new technique in the loss of heterozygosity (LOH) analysis at the E-cadherin gene locus in sporadic colon cancer. METHODS: One-hundred cases of human sporadic colon cancer and corresponding normal tissue samples were analyzed using two flanking polymorphic markers commonly used in the LOH analysis at the E-cadherin gene locus by conventional VNTR-LOH analysis. Two intragenic E-cadherin SNP markers were analyzed using real-time PCR SNP analysis. RESULTS: LOH (17.6%) was detected using flanking markers, however, no LOH was detected when the intragenic E-cadherin SNP markers were introduced into our study. Since these markers are intragenic they more accurately represent the status of the E-cadherin gene than the previously used flanking markers. CONCLUSION: In conclusion, real-time PCR SNP analysis was found to be more accurate, faster, simpler, and a more high-throughput method than the conventional VNTR-LOH analysis.

Biomarkers, Tumor↗
PubMed2004

Single nucleotide polymorphism analysis by chip-based hybridization and direct current electrical detection of gold-labeled DNA.

Single nucleotide polymorphism (SNP) analysis at the point of care requires a low cost detection technology that is capable of miniaturization, multiplexing, and high sensitivity. Direct current electrical detection (DCED) of DNA following nanoparticle labeling and silver enhancement is a promising candidate technology for point-of-care diagnostics. In this work we present, for the first time, SNP analysis in PCR products from patient samples using DCED, taking this platform technology a step closer to practical application. We developed a silane functionalized polymer for coating of biochip surfaces. This polymeric coating is stable under harsh conditions and has exceptionally high binding capacity. Allele-specific oligonucleotide probes were immobilized on chips coated with this polymer. Biotinylated PCR products of the human cholesteryl ester transfer protein gene from different patients were hybridized to the chips, labeled with gold nanoparticles, and autometallographically enhanced. The chips were scanned for DC electrical resistance by applying movable electrodes to the surface. Eighteen of nineteen patient samples were assigned the correct genotype. Our results demonstrate that SNP analysis of patient samples is feasible with DCED.

Affinity Labels↗
PubMed2002

Detection of allelic imbalance in ascitic supernatant by digital single nucleotide polymorphism analysis.

PURPOSE: Cytological examination of ascitic fluid is critical for clinical management of patients with peritoneal or pelvic diseases. Such morphological examination can only achieve a sensitivity of <62%, and thus a molecular test that is able to distinguish benign versus malignant ascites could be clinically useful. In this study we determined the presence of allelic imbalance (AI) in tumor-released DNA in ascitic supernatant by directly counting the alleles using a newly developed technology, digital single nucleotide polymorphism (SNP) analysis. EXPERIMENTAL DESIGN: Allelic status was assessed using a total of seven SNP markers that commonly demonstrated AI in ovarian, colorectal, and pancreatic cancers. RESULTS: With digital SNP analysis, AI in at least one SNP marker was found in 19 of 20 (95%) ascitic fluid DNA samples obtained from patients with cytologically proven carcinomas in ascitic fluid. In contrast, AI was detected in only 1 of 20 patients with negative cytology. This latter patient with AI in her ascites had known stage III ovarian carcinoma at the time of cytology sampling. The ascitic specimen of this patient demonstrated the presence of carcinoma cells in culture with an identical AI pattern found in the ascitic supernatant and surgical specimen. CONCLUSIONS: These findings suggest that detection of AI using digital SNP analysis can be a useful adjunct for the detection of ovarian and other types of cancer in ascitic fluid.

Alleles↗
PubMed2002

[DNA chip and SNP].

Single nucleotide polymorphism (SNP) is high-density genetic marker that could be utilized to dissect genetic traits that influence susceptibility to common diseases and responsiveness to drugs. Requirement for massive SNP analysis has enhanced development of various SNP genotyping technologies. DNA chip is one of such methods, which detects SNPs in parallel on an array of surface bound oligonucleotides. Recent application of DNA chip for high-throughput SNP analysis as well as clinical diagnosis will be presented.

Genetic Markers↗
PubMed2001

READIT: a novel technology used in the interrogation of nucleic acid sequences for single-nucleotide polymorphisms.

The ability to perform analyses for single-nucleotide polymorphisms (SNPs) has become routine in many molecular diagnostic laboratories. While various procedures and technologies are available to do so, we evaluated a novel technology for SNP analysis using the Factor V Leiden polymorphism as an example. The Factor V Leiden polymorphism G1691A is the most common genetic abnormality associated with hereditary thrombophilia. Current testing methods remain highly accurate yet their main disadvantage is gel-based detection. The READIT System (Promega Corp., Madison, WI) is a novel approach to SNP analysis that utilizes DNA polymerase-mediated pyrophosphorolysis to release dNTPs, which are converted to ATP and used in a luciferase detection reaction. We screened 280 DNA specimens, previously analyzed using the PCR/MnlI restriction digest assay, to evaluate READIT System capabilities along with the KingFisher robotic magnetic particle processor (ThermoLabsystems). Concordant results were obtained for 278/280 (99%) specimens. One discordant result was due to an equivocal relative light unit while the other was indeterminate. Both specimens gave correct results upon repeat analysis. The READIT System offers several advantages including: (1) rapid SNP analysis, (2) accuracy and precision, (3) cost effectiveness, (4) decreased turn-around times, (5) high throughput, and (6) excellent analysis software.

DNA↗
PubMed2001

Quantitative detection of single nucleotide polymorphisms for a pooled sample by a bioluminometric assay coupled with modified primer extension reactions (BAMPER).

A new method for SNP analysis based on the detection of pyrophosphate (PPi) is demonstrated, which is capable of detecting small allele frequency differences between two DNA pools for genetic association studies other than SNP typing. The method is based on specific primer extension reactions coupled with PPi detection. As the specificity of the primer-directed extension is not enough for quantitative SNP analysis, artificial mismatched bases are introduced into the 3'-terminal regions of the specific primers as a way of improving the switching characteristics of the primer extension reactions. The best position in the primer for such artificial mismatched bases is the third position from the primer 3'-terminus. Contamination with endogenous PPi, which produces a large background signal level in SNP analysis, was removed using PPase to degrade the PPi during the sample preparation process. It is possible to accurately and quantitatively analyze SNPs using a set of primers that correspond to the wild-type and mutant DNA segments. The termini of these primers are at the mutation positions. Various types of SNPs were successfully analyzed. It was possible to very accurately determine SNPs with frequencies as low 0.02. It is very reproducible and the allele frequency difference can be determined. It is accurate enough to detect meaningful genetic differences among pooled DNA samples. The method is sensitive enough to detect 14 amol ssM13 DNA. The proposed method seems very promising in terms of realizing a cost-effective, large-scale human genetic testing system.

Base Pair Mismatch↗
PubMed2004

Association study using combination analysis of SNP and STRP markers: CD14 promoter polymorphism and IgE level in Taiwanese asthma children.

Chromosome 5, especially the 5q31-33 region, may contain one or more loci to control total serum IgE as well as asthma and bronchial hyperresponsiveness. To investigate the regions related with IgE level in chromosome 5, we performed a case-control association study on 105 high-IgE-level and 85 normal-IgE-level asthmatic children using 43 microsatellite markers that span the whole chromosome 5 with 5 cM intervals. One of microsatellite marker, D5S2011, had significantly different allele frequency between the two asthmatic groups. E allele (143 bp) of the D5S2011 marker was more frequent in high-IgE asthmatics. CD14 is the candidate gene of atopy and asthma and is distant from D5S2011 by about 1 Mb. We analyzed the SNP genotypes in the CD14 gene region alone and in combination with microsatellite marker D5S2011. The CD14/-2984 polymorphism but not the CD14/-159 is associated with IgE level in Taiwanese asthmatic children. The CD14/-159 allele was observed only to be associated with IgE level when -159T was part of a haplotype containing a D5S2011 E allele. The combination analysis using SNP and STRP markers provided a novel method for increasing detection power in candidate gene association studies.

Adolescent↗
PubMed2002

Assessment of plasma DNA levels, allelic imbalance, and CA 125 as diagnostic tests for cancer.

BACKGROUND: Allelic imbalance (AI), the loss or gain of chromosomal regions, is found in many cancers. AI can be detected in genomic tumor DNA released into the blood after necrosis or apoptosis. We evaluated plasma DNA concentration, allelic status in plasma DNA, and serum CA 125 level as screening tests for ovarian and other cancers. METHODS: Plasma samples were obtained from 330 women (44 normal healthy control individuals, 122 patients with various cancers, and 164 control patients with non-neoplastic diseases). Plasma DNA concentration was determined in all samples. Allelic status was determined by digital single nucleotide polymorphism (SNP) analysis with eight SNP markers in plasma DNA from 54 patients with ovarian cancer and 31 control patients. CA 125 was determined in 63 samples. Receiver-operating characteristic (ROC) curves were plotted, and the areas under the ROC curves--a measure of the overall ability of a diagnostic test with multiple cutoffs to distinguish between diseased and nondiseased individuals--were determined. RESULTS: The area under the ROC curve for plasma DNA concentration was 0.90 for patients with neoplastic disease versus healthy control individuals and 0.74 for patients with neoplastic diseases versus control patients with non-neoplastic diseases. For control subjects given a specificity of 100% (95% confidence interval [CI] = 92% to 100%), the highest sensitivity achieved was 57% (95% CI = 49% to 67%). AI in at least one SNP was found in 87% (95% CI = 60% to 98%) of patients with stage I/II ovarian cancer and 95% (95% CI = 83% to 99%) of patients with stage III/IV ovarian cancer, but AI was not found in 31 patients with non-neoplastic diseases (specificity = 100%, 95% CI = 89% to 100%). The area under the ROC curve assessing AI was 0.95. Combining the serum CA 125 level with the plasma DNA concentration increased the area under the ROC curve from 0.78 (CA 125 alone) to 0.84. CONCLUSION: Plasma DNA concentration may not be sensitive or specific enough for cancer screening or diagnosis, even when combined with CA 125. AI was detected with high specificity in plasma DNA from patients with ovarian cancer and should be studied further as a screening tool.

Adult↗
PubMed2004

Use of single nucleotide polymorphism arrays to identify a novel region of loss on chromosome 6q in squamous cell carcinomas of the oral cavity.

BACKGROUND: A subset of patients with oral cavity squamous cell carcinoma(SCC), often of young age yet lacking a history of carcinogen exposure, has been identified, with no clear etiology for tumor development. METHODS: To identify somatic genetic alterations unique to this patient population, we performed a high throughput single nucleotide polymorphism (SNP) analysis, quantitative PCR of the E6 and E7 regions of human papillomavirus (HPV) 16, sequencing of the IVSF-4+ locus of the FANC-C gene, and microsatellite analysis for 18 nonsmoking patients, age 23 to 57 years (median age, 39 years). We compared these results with oral SCC from 17 patients 47 to 81 (median, 64) years of age with significant tobacco exposure (>40 pack-years) to identify unique genetic alterations for each group. RESULTS: SNP analysis demonstrated variable rates of allelic imbalance (AI) and no significant difference in terms of AI patterns between the two groups. However, we found an elevated rate of AI in chromosomal arms 6q (47% [17 of 36]) by performing microsatellite analysis of both groups. Only one tumor demonstrated the presence of HPV 16, and none of the tumors demonstrated mutations in the IVSF-4+ region of FANC-C. CONCLUSIONS: Despite variable marker density, SNP array analysis is an emerging technique for genome-wide assessment and is a useful tool for discovery of novel sites of allelic loss in oral SCC, including a novel region of allelic loss on chromosome 6q.

Adult↗
PubMed2003

Single-nucleotide polymorphism detection in plants using a single-stranded pyrosequencing protocol with a universal biotinylated primer.

Analysis of variations in plant genomes is increasingly focused on single-nucleotide polymorphism (SNP) analysis, increasing the need for fast yet reliable, simple, and cost-effective techniques to handle the large number of these polymorphisms within large plant genomes. Pyrosequencing technology offers a technique that takes advantage of the interaction of four enzymes in a single-tube assay to measure DNA synthesis in real time. Pyrosequencing provides a DNA sequence and an advantage over alternative techniques in poorly characterized genomes such as those of most plant species. Here we compare the use of both single-stranded and double-stranded template Pyrosequencing on plant tissue for SNP identification. Different enzymatic strategies for double-stranded template preparation were compared. Preparation of double-stranded template from plant tissue required labor-intensive purification to allow double-stranded Pyrosequencing. A more cost-effective and less labor-intensive alternative to double-stranded template preparation in plants has been developed using a universal biotinylated primer to improve the efficiency of single-stranded Pyrosequencing. This provides an efficient high-throughput method for SNP analysis by Pyrosequencing.

Biotinylation↗
PubMed2005

SNP microarray analysis for genome-wide detection of crossover regions.

There is a great deal of interest in understanding the non-random distribution of recombination events over the human genome, because it has important implications for using linkage disequilibrium (LD) to identify human disease genes. So far, only a few recombination hotspots in the human genome have been characterised and the identification of new crossover hotspots will contribute to a better understanding of the mechanisms that govern their formation and distribution. This study shows that high-density single nucleotide polymorphism (SNP) arrays, together with the presented analysis method, are an appropriate tool for generating a whole-genome recombination pattern and for detecting new crossover regions with enhanced recombination frequency. Based on the genotype data of 16 members of a Caucasian three-generation family, we identified 825 crossover regions. The average recombination frequency of females and males was 0.77 and 0.56 cM/Mb, respectively. We detected 24 crossover regions showing elevated recombination activity, which comprised known hotspots, like the MHC II region, confirming the non-random distribution of recombination events along the genome. Interestingly, 29.2% of the identified crossover hotspot regions overlapped with regions flanked by segmental duplications published by Bailey et al. (Science 297:1003-1007, 2002) suggesting that segmental duplications and crossover hotspot regions are mechanistically linked. By extrapolating the results of the present study, we conclude that it might be feasible, at least in part, to estimate to what extent the block-like pattern of LD exactly relies on the genome-wide crossover pattern using the next generation high-density SNP microarrays.

Crossing Over, Genetic↗
PubMed2003

Approach to analysis of single nucleotide polymorphisms by automated constant denaturant capillary electrophoresis.

Melting gel techniques have proven to be amenable and powerful tools in point mutation and single nucleotide polymorphism (SNP) analysis. With the introduction of commercially available capillary electrophoresis instruments, a partly automated platform for denaturant capillary electrophoresis with potential for routine screening of selected target sequences has been established. The aim of this article is to demonstrate the use of automated constant denaturant capillary electrophoresis (ACDCE) in single nucleotide polymorphism analysis of various target sequences. Optimal analysis conditions for different single nucleotide polymorphisms on ACDCE are evaluated with the Poland algorithm. Laboratory procedures include only PCR and electrophoresis. For direct genotyping of individual SNPs, the samples are analyzed with an internal standard and the alleles are identified by co-migration of sample and standard peaks. In conclusion, SNPs suitable for melting gel analysis based on theoretical thermodynamics were separated by ACDCE under appropriate conditions. With this instrumentation (ABI 310 Genetic Analyzer), 48 samples could be analyzed without any intervention. Several institutions have capillary instrumentation in-house, thus making this SNP analysis method accessible to large groups of researchers without any need for instrument modification.

Algorithms↗
PubMed2003

The out of Africa model of varicella-zoster virus evolution: single nucleotide polymorphisms and private alleles distinguish Asian clades from European/North American clades.

Until 1998, varicella-zoster virus (VZV) was generally considered sufficiently stable to allow the use of a single sequenced virus (VZV-Dumas) as a consensual representation of the world VZV genotype. But recent investigations have uncovered a gE mutant virus called VZV-MSP with a second genotype and a distinguishable accelerated cell spread phenotype. A subsequent study suggested that single nucleotide polymorphisms (SNPs) could be applied toward the genetic analysis of the VZV genome. To further assess the scope of genetic variation in the VZV genome on a worldwide basis, we carried out an extensive SNP analysis of structural glycoprotein genes gB, gE, gH, gI, gL, as well as the IE62 regulatory gene in viruses collected from Western Europe, North America and Asia, including the VZV vaccine strain. The SNP data showed segregation of viral isolates of Asian origin from those of Western ancestry into distinct phylogenetic clades. Unexpectedly, however, VZV from Thailand segregated with VZV from Iceland and the United States, i.e. it was more Western than Asian in nature. Further, SNP analysis disclosed strikingly unusual genotypes, e.g. gH genes with up to five missense mutations and gL genes with insertions of an in-frame methionine codon. In summary, these VZV genomic analyses have shown that individual VZV strains, like closely related human beings, have distinctive SNP profiles containing private alleles within just five VZV genes (gB, gH, gE, gL and IE62) that provide a fingerprint to localize ancestry of the viral strain.

Africa↗
PubMed2006

Genome-wide SNP assay reveals structural genomic variation, extended homozygosity and cell-line induced alterations in normal individuals.

The recent hapmap effort has placed focus on the application of genome-wide SNP analysis to assess the contribution of genetic variability, particularly SNPs, to traits such as disease. Here, we describe the utility of genome-wide SNP analysis in the direct detection of extended homozygosity and structural genomic variation. We use this approach to assess the frequency of genomic alterations resulting from the lymphoblast immortalization and culture processes commonly used in cell repositories. We have assayed 408 804 SNPs in 276 DNA samples extracted from Epstein-Barr virus immortalized cell lines, which were derived from lymphocytes of elderly neurologically normal subjects. These data reveal extended homozygosity (contiguous tracts >5 Mb) in 9.5% (26/272) and 340 structural genomic alterations in 182 (66.9%) DNA samples assessed, 66% of which did not overlap with previously described structural variations. Examination of DNA extracted directly from the blood of 30 of these subjects confirmed all examined instances of extended homozygosity (6/6), 75% of structural genomic alteration <5 Mb in size (12/16) and 13% (1/8) of structural genomic alteration >5 Mb in size. These data suggest that structural genomic variation is a common phenomenon in the general population. While a proportion of this variability may be caused or its relative abundance altered by the immortalization and clonal process this will have only a minor effect on genotype and allele frequencies in a large cohort. It is likely that this powerful methodology will augment existing techniques in the identification of chromosomal abnormalities.

Aged↗