An area on a
chromosome where
transcription of
DNA into
mRNA, or
replication of DNA is occurring, resulting in an enlarged, puffy appearance of the area. Similar to a
chromosome puff, except generalized to any type of chromosome in any type of
organism.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.