Omni tip disposable generator probes

DNA was extracted from 25–50 mg of LAA tissue. The tissue, in one mL of DNAzol® (Invitrogen), was homogenized (PowerGen700, Fisher Scientific) with sterile Omni Tip Disposable Generator Probes (Omni International). DNA was isolated from the homogenate following the DNAzol protocol. The DNA pellet was resuspended in 20 μl of 10 mM Tris buffer (pH 7.4) and the DNA concentration was optically evaluated (OD₂₆₀ nm), diluted to 100 ng/μl and stored at −80°C until use. DNA was genotyped using Illumina Hap550v3 and Hap610-quad SNP microarrays. SNP data were imputed to 1000 Genomes Project phase 2 yielding ~19 million SNPs, using IMPUTE^{10 (link)} after filtering out variants falling below 0.5 on IMPUTE’s information statistic. For the eQTL analysis, we excluded SNPs with < 5% and <10% minor allele frequency in the European descent and African American cohorts resulting in roughly 6.8 and 6.6 million SNPs per cohort, respectively.