Consenting donors or volunteers from the local ethnic population group of Shillong have been recruited in the study, which is ongoing. Withdrawal of blood, irradiation, postirradiation incubation, and qPCR methodology has been described in details recently.[27 (link)28 ] Blood samples were irradiated, subjected to postirradiation incubation as described in section on “Sample preparation, radiation dose, and downstream processing” and total RNA was isolated directly from the blood using Trizol BD reagent (Sigma-Aldrich, USA) as per the manufacturer's recommendations. RNA sample (1 µg) was converted into cDNA using the high-capacity DNA-archive kit (Applied Biosystems, USA) and following the manufacturer's instructions. qPCR was done using the gene-specific TaqMan™ assays (Applied Biosystems, USA). The gene expression change has been calculated as fold change utilizing the “ΔΔCt” method. Thus, the gene expression fold change is expressed as 2−ΔΔCt. The data were evaluated using the Sequence Detection Software 1.3.1 (Applied Biosystems, USA). Statistical evaluation of the generated data was performed using one-way ANOVA for both the irradiated samples with respect to controls as well as the individual samples with respect to each other. The 18S-rRNA and GAPDH TaqMan™ assays were selected as the endogenous controls or normalizers.[27 (link)]