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The DASL (cDNA-mediated Annealing, Selection, extension and Ligation) assay has been specifically designed as a gene expression profiling system to generate reproducible data from degraded RNAs such as those derived from formalin-fixed paraffin-embedded (FFPE) tumor samples. The assay is a cross between microarray and qRT-PCR technologies and can be used to analyze expression of a panel of selected genes in a single clinical sample using a minimal amount of total RNA (100-200 ng RNA per assay). The DASL assay has high reproducibility on FFPE tissue samples as old as 24 years, high throughput (up to 96 clinical samples on one array plate), and allows for custom gene panels (up to 512 genes per array).
Details on the DASL Assay can be found here: DASL.pdf and here: DASL_techbulletin.pdf In the procedure, random priming is used for cDNA synthesis and the size of the targeted gene sequence is small (50 nucleotides), enabling analysis of RNAs that are otherwise too degraded for conventional microarray analysis.
Illumina GoldenGate SNP detection The DASL assay can also be used to detect up to 1536 single nucleotide polymorphisms (SNPs) in genomic DNA.
Illumina DASL DNA methylation assay By pretreating with bisulphate, a C/T SNP assay can quantitate DNA methylation at up to 768 genomic loci.