chromosome puff


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chromosome puff

A localised separation of polytene chromosomes (e.g., chromosomes of Drosophila melanogaster) that represents a site of active RNA synthesis—i.e., transcription—which, when very large, is known as a Balbiani ring.

chromosome puff

or

puff

a cloudy area visible on specific CHROMOMERES of SALIVERY GLAND CHROMOSOMES at certain times. Chromosome puffs contain DNA and RNA and are thought to represent gene TRANSCRIPTION. This idea is reinforced by the fact that such puffs occur at regular intervals, suggesting that GENE SWITCHING is in operation.
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