Tissue specific genomics of human brain in healthy and glioblastoma patients. Homo sapiens

The objective of this study was to identify and analyze somatic variations in healthy human tissues. For this we obtained paired tissue from nine individuals. Four tissue pairs represented neuronal and non-neuronal parts of the brain - frontal cortex (FC) and corpus callosum (CC), respectively. These were from post-mortem, road accident victims. The other five tissue pairs were from blood and saliva of unrelated healthy adults. Exome enrichment was performed on DNA isolated from these 18 samples using Illumina Tru-Seq chemistry and then sequenced on Hi-Seq2000 (100 base pair, paired-end). The sequence reads were filtered for quality and then aligned against the reference human genome (hg19) using BWA. We observed brain to harbor more somatic variations than other tissue types – and majority of them were transversions likely to have occurred due to oxidative stress.