Definition of "heterochromatin" [heterochromatin]

• Tightly coiled chromosomal material that stains deeply during interphase and is believed to be genetically inactive. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• ""In recent years it has become apparent that heterochromatin is critical for many essential functions.""
• ""These modifications cause parts of chromosomes to condense into so-called heterochromatin, burying the regulatory regions of p53 target genes deep within," says graduate student and co-first author Fanny E. Estermann."
• "In general, C-bands and G-bands are complexed with proteins and RNAs to give a more compact organization called heterochromatin, whereas R-bands have a more open conformation referred to as euchromatin."