QTL Mapping of Molecular Traits for Studies of Human Complex Diseases

Abstract

Genetic mapping of quantitative trait loci (QTL) offers a powerful and efficient approach to discover putative regulatory regions of traits and to define novel functional implications of genetic variants. Here we reviewed recent progress on QTL mapping of molecular traits, including gene expression, DNA methylation, as well as protein expression, metabolites. QTL mapping of molecular traits has better chance to succeed in relatively small sample size study as fewer nongenetic factors or gene-gene interactions may involve. Knowledge derived from QTL mapping will help us to uncover understanding of biology in complex traits and diseases and enhance power of genetic association study. In the context of study of complex diseases, we focused on expression QTL and methylation QTL, presenting major findings and technique considerations, including experimental platform, sample quality, size, and heterogeneity, as well as analytical procedure and significance criteria. Lastly, we discussed the current and future use of QTL data in study of complex diseases.