MALDI-TOF MS
This process of MALDI-TOF MS combines the technologies of mass spectrometry and PCR and primer extension to determine each allele. The first step in this process is to perform PCR to amplify the region surrounding the SNP. Second step is to treat the PCR reactions with shrimp alkaline phosphatase to dephosphorylate unincorporated nucleotides. In the third step a single base extension (SBE) reaction is performed using thermo sequenase to incorporate mass modified dideoxy nucleotides. This post-PCR primer extension reaction generates small DNA products that have unique mass value based on each allele. These mass extension products are spotted on a chip consisting of matrix that will help in the ionization of the DNA products when exposed to high intensity laser. The time of flight of these ionized products will depend on the mass of each allele that will be measured by the mass spectrometer. The entire process is completely automated including assay development, PCR setup, post-PCR treatment, nanoliter transfer of extension products to chips, serial reading of chip positions in the mass spectrometer, and final analytical interpretation. The mass modified SBE nucleotides allow for use of highly stringent calling thresholds and performance at high plex levels. This platform utilizes minimal DNA, 5-10 ng of DNA per set of multiplexed assays and provides call rates of greater than 95% on high quality samples that are accurately quantitated.
Instruments
Liquid Handling Systems, Nanodispensor, MALDI-TOF Analyzer, Infomatic Analytics Server, Computer control system, Genotyping and Assay Design softwares
Automation
MassARRAY provides 3 stops automation system: 1. Liquid Handling Systems; 2. sample porting by. Nanodispensor 3. multiple sampling and analyses automatically by Analyzer & Software.
screen
Based on 20 PCR reactions per each well, 20 pcs of chips can be screened within 9 hours. It¡¯s about 150000 SNP genotyping.
sample
5ul of 2-2.5ng DNA.
probe
3 pcs of oligo, length of which is 17-24bp each.
others
4 SNP sites at least in the project can be performed and the allele gene frequency analysis can be provided.
other applications
¡ôallele gene frequency confirmation.
¡ôquantitive analysis of gene expression
¡ôSNP discovery.
¡ôoligo quality control.
¡ôDNA methylation analysis.
Contact
E-mail: snp@generay.com.cn
Tel: +86-21-67626120
Web: http://www.generay.com.cn/English
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