A high-density SNP genotyping array for Brassica napus and its ancestral diploid species based on optimised selection of single-locus markers in the allotetraploid genome.

The Brassica napus Illumina array provides genome-wide markers linked to the available genome sequence, a significant tool for genetic analyses of the allotetraploid B. napus and its progenitor diploid genomes. A high-density single nucleotide polymorphism (SNP) Illumina Infinium array, containing 52,157 markers, was developed for the allotetraploid Brassica napus.

A panel of CpG methylation sites distinguishes human embryonic stem cells and induced pluripotent stem cells.

Whether human induced pluripotent stem cells (hiPSCs) are epigenetically identical to human embryonic stem cells (hESCs) has been debated in the stem cell field. In this study, we analyzed DNA methylation patterns in a large number of hiPSCs (n = 114) and hESCs (n = 155), and identified a panel of 82 CpG methylation sites that can distinguish hiPSCs from hESCs with high accuracy. We show that 12 out of the 82 CpG sites were subject to hypermethylation in part by DNMT3B.

High density DNA methylation array with single CpG site resolution.

We have developed a new generation of genome-wide DNA methylation BeadChip which allows high-throughput methylation profiling of the human genome. The new high density BeadChip can assay over 480K CpG sites and analyze twelve samples in parallel. The innovative content includes coverage of 99% of RefSeq genes with multiple probes per gene, 96% of CpG islands from the UCSC database, CpG island shores and additional content selected from whole-genome bisulfite sequencing data and input from DNA methylation experts.

On the future of genomic data.

Many of the challenges in genomics derive from the informatics needed to store and analyze the raw sequencing data that is available from highly multiplexed sequencing technologies. Because single week-long sequencing runs today can produce as much data as did entire genome centers a few years ago, the need to process terabytes of information has become de rigueur for many labs engaged in genomic research. The availability of deep (and large) genomic data sets raises concerns over information access, data security, and subject/patient privacy that must be addressed for the field to continue its rapid advances.

Genome-wide DNA methylation profiling.

DNA methylation plays a critical role in the regulation of gene expression. The ability to access the methylation status for a large number of genes or the entire genome should greatly facilitate the understanding of the nature of gene regulation in cells, and epigenetic mechanism of interactions between cells and environment. Microarray and sequencing-based DNA methylation profiling technologies have been developed to meet this goal.

Highly sensitive and specific microRNA expression profiling using BeadArray technology.

We have developed a highly sensitive, specific and reproducible method for microRNA (miRNA) expression profiling, using the BeadArray technology. This method incorporates an enzyme-assisted specificity step, a solid-phase primer extension to distinguish between members of miRNA families. In addition, a universal PCR is used to amplify all targets prior to array hybridization.

Using Support Vector Machine Regression to Model the Retention of Peptides in Immobilized Metal-affinity Chromatography.

Retention of histidine-containing peptides in immobilized metal-affinity chromatography (IMAC) has been studied using several hundred model peptides. Retention in a Nickel column is primarily driven by the number of histidine residues; however, the amino acid composition of the peptide also plays a significant role. A regression model based on support vector machines was used to learn and subsequently predict the relationship between the amino acid composition and the retention time on a Nickel column.

Expression signatures that correlated with Gleason score and relapse in prostate cancer.

Predicting prognosis in prostate carcinoma remains a challenge when using clinical and pathologic criteria only. We used an array-based DASL assay to identify molecular signatures for predicting prostate cancer relapse in formalin-fixed, paraffin-embedded (FFPE) prostate cancers, through gene expression profiling of 512 prioritized genes. Of the 71 patients that we analyzed, all but 3 had no evidence of residual tumor (defined as negative surgical margins) following radical prostatectomy and no patient received adjuvant therapy following surgery.

Highly parallel genomic assays.

Recent developments in highly parallel genome-wide assays are transforming the study of human health and disease. High-resolution whole-genome association studies of complex diseases are finally being undertaken after much hypothesizing about their merit for finding disease loci. The availability of inexpensive high-density SNP-genotyping arrays has made this feasible.

A method for rapid protease substrate evaluation and optimization.

We have developed a high throughput assay for the measurement of protease activity in solution. This technology will accelerate research in functional proteomics and enable biologists to streamline protease substrate evaluation and optimization. The peptide sequences that serve as protease substrates in this assay are labeled on the carboxy terminus with a biotin moiety and a fluorescent tag is attached to the amino terminus.

Synthetic modification of silica beads that allows for sequential attachment of two different oligonucleotides.

We developed a simple and elegant synthesis strategy that enables us to attach controlled (equimolar) amounts of two different oligonucleotides onto one silica bead. The method involves addition of orthogonally protected lysine followed by activation and derivatization of each amino group with a different moiety. This sequential oligonucleotide attachment enables the use of a combinatorial scheme to generate millions of bead types, each characterized by its two oligo tags.

Evaluation of linkage disequilibrium and its effect on non-parametric multipoint linkage analysis using two high density single-nucleotide polymorphism mapping panels.

Genotype data from the Illumina Linkage III SNP panel (n = 4,720 SNPs) and the Affymetrix 10 k mapping array (n = 11,120 SNPs) were used to test the effects of linkage disequilibrium (LD) between SNPs in a linkage analysis in the Collaborative Study on the Genetics of Alcoholism pedigree collection (143 pedigrees; 1,614 individuals). The average r2 between adjacent markers across the genetic map was 0.099 +/- 0.

Whole-genome genotyping with the single-base extension assay.

We describe an efficient, accurate and robust whole-genome genotyping (WGG) assay based on a two-color, single-base extension (SBE), single-nucleotide polymorphism (SNP)-scoring step. We report genotyping results for biallelic International HapMap quality control (QC) SNPs using a single probe per locus. We show scalability, throughput and accuracy of the system by resequencing homozygous loci from our 100k Human-1 Genotyping BeadChip.

Illumina, Inc.

Illumina, Inc., based in San Diego (CA, USA), is a genomics tool company that develops and markets integrated array-based systems and assays for a broad range of applications including genotyping, gene expression and epigenetics. Product offerings range from focused assay sets (up to 1,536 multiplexed assays) to whole-genome analysis (>100,000 assays/sample).

The External RNA Controls Consortium: a progress report.

Standard controls and best practice guidelines advance acceptance of data from research, preclinical and clinical laboratories by providing a means for evaluating data quality. The External RNA Controls Consortium (ERCC) is developing commonly agreed-upon and tested controls for use in expression assays, a true industry-wide standard control.

High-throughput SNP genotyping on universal bead arrays.

We have developed a flexible, accurate and highly multiplexed SNP genotyping assay for high-throughput genetic analysis of large populations on a bead array platform. The novel genotyping system combines high assay conversion rate and data quality with >1500 multiplexing, and Array of Arrays formats. Genotyping assay oligos corresponding to specific SNP sequences are each linked to a unique sequence (address) that can hybridize to its complementary strand on universal arrays.

A highly informative SNP linkage panel for human genetic studies.

We have developed a highly informative set of single-nucleotide polymorphism (SNP) assays designed for linkage mapping of the human genome. These assays were developed on a robust multiplexed assay system to provide a combination of very high accuracy and data completeness with high throughput for linkage studies. The linkage panel is comprised of approximately 4,700 SNPs with 0.

Simple tools for resin distribution.

Two simple instruments allowing uniform distribution of resin beads for solid-phase synthesis are described. The first tool simplifies distribution of resin into microtiterplates. The second tool was designed for distribution of a variable amount of resin beads into any number of reaction vessels, and the technique is applicable to resin beads with a wide range of physical properties (density).

Efficient strategies for the conjugation of oligonucleotides to antibodies enabling highly sensitive protein detection.

Three methods for the conjugation of oligonucleotides to antibodies and the subsequent application of these conjugates to protein detection at attomole levels in immunoassays are described. The methods are based on chemical modification of both antibody and oligonucleotide. Aldehydes were introduced onto antibodies by modification of primary amines or oxidation of carbohydrate residues.

Strategies for covalent attachment of DNA to beads.

Several covalent attachment chemistries were tested for the immobilization of DNA onto glass beads. The comparison was based on the ability of these chemistries to produce derivatized beads that give good hybridization signals. Cyanuric chloride, isothiocyanate, nitrophenyl chloroformate, and hydrazone chemistries gave us the best (yet comparable) hybridization signals.