Puffs are characteristic of polytene chromosomes found in salivary glands of Drosophila and contain large quantities of mRNA. The appearance of puffs is correlated with the intense secretory activity which the larval salivary glands have to perform.
What is chromosome puff?
A swelling at a site along the length of a polytene chromosome; the site of active transcription. A diffuse uncoiled region in a polytene chromosome where transcription is actively taking place.
What is occurring at the chromosome 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.
What are DNA puffs?
DNA puffs are genomic regions of polytene chromosomes that undergo developmentally controlled DNA amplification and transcription in salivary glands of sciarid flies. … To do that, we generated antibodies against saliva and immunoscreened a cDNA library made from salivary glands.
What are Balbiani rings?
Balbiani rings are exceptionally large puffs on the polytene chromosomes in the dipteran Chironomus tentans. These puffs are particularly well suited for studies of the structure of active genes and the synthesis and transport of specific RNA-protein (RNP) particles.
Are chromosome puffs reversible?
Puffs are reversible structural modifications to chromosomes which result in the local decondensation of, usually, a single band.
What are chromosome 2 traits?
Individuals with this chromosome abnormality often have developmental delay, small head size (microcephaly), slow growth before and after birth, heart defects, and distinctive facial features. The severity of symptoms typically depends on how many and which types of cells contain the ring chromosome 2.
What is the difference between polytene chromosome and Lampbrush chromosome?
The main difference between polytene and lampbrush chromosome is that polytene chromosomes occur in the salivary glands and other tissues of insects whereas lampbrush chromosomes occur in the oocytes of vertebrates except for mammals and some invertebrates.
Which portion of the chromosome is referred to as the Balbiani ring?
Chromosome puffs. … Electron micrographs of certain puffs, called Balbiani rings, of Chironomus salivary gland polytene chromosomes show the chromatin arranged in loops (Figures 4-42 and 4-43), much like those observed in the amphibian lampbrush chromosomes discussed earlier.