Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí sinh học đề tài : Buffy coat specimens remain viable as a DNA source for highly multiplexed genome-wide genetic tests after long term storage | Mychaleckyj et al. Journal of Translational Medicine 2011 9 91 http content 9 1 91 JOURNAL OF TRANSLATIONAL MEDICINE RESEARCH Open Access Buffy coat specimens remain viable as a DNA source for highly multiplexed genome-wide genetic tests after long term storage 1 1 2 1 3 4 Josyf C Mychaleckyj Emily A Farber Jessica Chmielewski Jamie Artale Laney S Light Donald W Bowden Xuanlin Hou1 and Santica M Marcovina2 Abstract Background Blood specimen collection at an early study visit is often included in observational studies or clinical trials for analysis of secondary outcome biomarkers. A common protocol is to store buffy coat specimens for future DNA isolation and these may remain in frozen storage for many years. It is uncertain if the DNA remains suitable for modern genome wide association GWA genotyping. Methods We isolated DNA from 120 Action to Control Cardiovascular Risk in Diabetes ACCORD clinical trial buffy coats sampling a range of storage times up to 9 years and other factors that could influence DNA yield. We performed TaqMan SNP and GWA genotyping to test whether the DNA retained integrity for high quality genetic analysis. Results We tested two QIAGEN automated protocols for DNA isolation preferring the Compromised Blood Protocol despite similar yields. We isolated DNA from all 120 specimens yield range ug per ml ACD tube of whole blood with only 3 120 samples yielding 10 ug DNA. Age of participant at blood draw was negatively associated with yield mean change ug year . DNA quality was very good based on gel electrophoresis QC TaqMan genotyping of 6 SNPs genotyping no-call rate in 702 genotypes and excellent quality GWA genotyping data maximum per sample genotype missing rate . Conclusions When collected as a long term clinical trial or biobank specimen for DNA buffy coats can be stored for up to 9 years in a -80degC frozen state and still produce high yields of DNA suitable for GWA analysis and .
