With many questions about DNA now answered, scientists are now looking at genes in a broader context. For example, how do they interact with the environment? What can we learn from gene expression profiles of different tissues in the body? Information like this can be used widely in a range of research projects and to better understand disease and improve people’s lives.
The study of epigenetics looks at how the environment affects gene expression. Epigenetic changes, however, do not affect the DNA sequence directly. For example, smoking changes the methylation of genes, blocking proteins needed for those genes to function properly. Stopping smoking can restore methylation to normal levels.
Source: What is Epigenetics? | CDC ]
ENCODE, or the Encyclopedia of DNA Elements, started in 2003 with the goal of building a list of functional elements in the human and mouse genome. Since then, the project has conducted many assays to identify those elements in humans and mice. The data produced from this work is housed in a freely accessible database for public and research use.
The application of next-generation sequencing methodologies to sequence other nucleic acid molecules such as RNA enabled the characterization of human gene expression profiles or transcriptomes at scale in different human tissues through the Genotype-Tissue Expression (GTEx) Project.