Chromatin

• the part of the nucleus that stains well
  Source: Noland, George B. 1983. General Biology, 11th Edition. St. Louis, MO. C. V. Mosby
• the DNA-protein complex of chromosomes
  Source: Jenkins, John B. 1990. Human Genetics, 2nd Edition. New York: Harper & Row
• Chromatin is a substance within a chromosome consisting of DNA and protein. The DNA carries the cell's genetic instructions. The major proteins in chromatin are histones, which help package the DNA in a compact form that fits in the cell nucleus. Changes in chromatin structure are associated with DNA replication and gene expression.