The different environments that humans experience are likely to impact
physiology and disease susceptibility. In order to estimate the magnitude
of the impact of environment on transcript abundance, we examined gene
expression in peripheral blood leukocyte samples from 46 desert nomadic,
mountain agrarian and coastal urban Moroccan Amazigh individuals. Despite
great expression heterogeneity in humans, as much as one third of the
leukocyte transcriptome was found to be associated with differences among
regions. Genome-wide polymorphism analysis indicates that genetic
differentiation in the total sample is limited and is unlikely to explain
the expression divergence. Methylation profiling of 1,505 CpG sites
suggests limited contribution of methylation to the observed differences
in gene expression. Genetic network analysis further implies that specific
aspects of immune function are strongly affected by regional factors and
may influence susceptibility to respiratory and inflammatory disease. Our
results show a strong genome-wide gene expression signature of regional
population differences that presumably include lifestyle, geography, and
biotic factors, implying that these can play at least as great a role as
genetic divergence in modulating gene expression variation in humans. Supplementary
FiguresMoroccoSuppFig.pdfSupplementary TablesMoroccoSuppTables.pdfZipped Extra Supplementary TablesIdaghdourextsupptables.zipSupplementary Table S2IdaghdourTableS2.xlsSupplementary Table S3IdaghdourTableS3.xlsSupplementary Table S4IdaghdourTableS4.xlsCombined DatasetCombined_Morocco.xls