# Background ## 3D Genomics If the DNA from a single cell was taken out and stretched end to end, it would span 2 meters. But all that DNA has to fold up tightly inside a single nucleus only a few microns wide. Studying the patterns and rules of DNA folding, and the implications this folding has for disease or epigenetics is the field of 3D genomics. Hi-C data represent one major approach for studying 3D interactions within the cell, using a technique known as contact mapping. See more below from Dr. Erez Aiden's talk at the Scripps Research Translational Institute. {% embed url="" %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://aidenlab.gitbook.io/juicebox/background.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.