Tissue-specific and trait-associated variation of human DNA methylation

Epigenetics refers to a host of different mechanisms that regulate the expression levels of genes in an organism that do not rely on direct changes to the DNA sequence. These marks are heritable and sensitive to external signals. One epigenetic mechanism is DNA methylation, which consists on the attachment of a methyl group to a CpG dinucleotide. With the use of microarrays, DNA methylation studies typically interrogate the methylation status of hundreds of thousands of CpG sites in cohorts that range from tens to hundreds of individuals. In this thesis we identify tissue-specific and trait-specific patterns of methylation and highlight biological features associated with them. We also quantify the extent to which DNA methylation can optimally encode information about certain human traits.