The Encyclopedia of DNA Elements (ENCODE) is a public research project which aims "to build a comprehensive parts list of functional elements in the human genome." ENCODE also supports further biomedical research by "generating community resources of genomics data, software, tools and methods for genomics data analysis, and products resulting from data analyses and interpretations." The current phase of ENCODE (2016-2019) is adding depth to its resources by growing the number of cell types, data types, assays and now includes support for examination of the mouse genome. ENCODE was launched by the US National Human Genome Research Institute (NHGRI) in September 2003. Intended as a follow-up to the Human Genome Project, the ENCODE project aims to identify all functional elements in the human genome. The project involves a worldwide consortium of research groups, and data generated from this project can be accessed through public databases. The initial release of ENCODE was in 2013 and since has been changing according to the recommendations of consortium members and the wider community of scientists who use the Portal to access ENCODE data. The two-part goal for ENCODE is to serve as a publicly accessible data base for "experimental protocols, analytical procedures and the data themselves," and "the same interface should serve carefully curated metadata that record the provenance of the data and justify its interpretation in biological terms." The project began its fourth phase (ENCODE 4) in February 2017. Humans are estimated to have approximately 20,000 protein-coding genes, which account for about 1.5% of DNA in the human genome. The primary goal of the ENCODE project is to determine the role of the remaining component of the genome, much of which was traditionally regarded as "junk". The activity and expression of protein-coding genes can be modulated by the regulome - a variety of DNA elements, such as promoters, transcriptional regulatory sequences, and regions of chromatin structure and histone modification.