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updated: September 23, 2023


Chromatin refers to a mixture of DNA and proteins that form the chromosomes found in the cells of humans and other higher organisms. Many of the proteins — namely, histones — package the massive amount of DNA in a genome into a highly compact form that can fit in the cell nucleus.



Chromatin. The total DNA in the cell is about 5 to 6 feet long which has to fit inside the nucleus of a cell in an orderly fashion. DNA molecules first wrap around the histone proteins forming beads on string structure called nucleosomes. Nucleosomes further [inaudible] and condense/gather to form fibrous material which is called chromatin. Chromatin fibers can unwind for DNA replication and transcription. When cells replicate, duplicated chromatins condense further to become a lot like chromosomes, visible under microscope which are separated into daughter cells during cell division.

Paul Liu
Paul P. Liu, M.D., Ph.D.

Deputy Scientific Director

Senior Investigator, Translational and Functional Genomics Branch