RT Journal Article
SR Electronic
T1 Human Gene Expression Variability and its Dependence on Methylation and Aging
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 500785
DO 10.1101/500785
A1 Nasser Bashkeel
A1 Theodore J. Perkins
A1 Mads Kærn
A1 Jonathan M. Lee
YR 2019
UL http://biorxiv.org/content/early/2019/11/14/500785.abstract
AB Background Phenotypic variability of human populations is partly the result of gene polymorphism and differential gene expression. As such, understanding the molecular basis for diversity requires identifying genes with both high and low population expression variance and identifying the mechanisms underlying their expression control. Key issues remain unanswered with respect to expression variability in human populations. The role of gene methylation as well as the contribution that age, sex and tissue-specific factors have on expression variability are not well understood.Results Here we used a novel method that accounts for sampling error to classify human genes based on their expression variability in normal human breast and brain tissues. We find that high expression variability is almost exclusively unimodal, indicating that variance is not the result of segregation into distinct expression states. Genes with high expression variability differ markedly between tissues and we find that genes with high population expression variability are likely to have age-, but not sex-dependent expression. Lastly, we find that methylation likely has a key role in controlling expression variability insofar as genes with low expression variability are likely to be non-methylated.Conclusions We conclude that gene expression variability in the human population is likely to be important in tissue development and identity, methylation, and in natural biological aging. The expression variability of a gene is an important functional characteristic of the gene itself and the classification of a gene as one with Hyper-Variability or Hypo-Variability in a human population or in a specific tissue should be useful in the identification of important genes that functionally regulate development or disease.List of AbbreviationsAUApproximately UnbiasedEGAEuropean Genome-Phenome ArchiveEMExpectation-MaximizationEVExpression VariabilityGEOGene Expression OmnibusGOGene OntologyMADMedian Absolute DeviationMVMethylation VariabilityPMIPost-Mortem IntervalUKBECUK Human Brain Expression Database