Question

What genetic process is occurring in a puff of a polytene chromosome?

Short answer

Answer: The genetic process occurring in a puff of a polytene chromosome is gene expression.

Step-by-step solution

Understand Polytene Chromosomes

Polytene chromosomes are a type of chromosome found in certain cells of certain organisms, such as the salivary glands of the fruit fly (Drosophila melanogaster). These chromosomes are formed by repeated rounds of DNA replication without cell division (endoreplication), resulting in many copies of the chromosome lying side by side, giving the appearance of a thick, banded structure when viewed under a microscope.

Identify the Puff

In the polytene chromosome, puffs are the regions where significant gene activity takes place. They appear as swollen, less-condensed regions along the chromosomes, which usually correspond to active transcription and loading of specific RNA polymerase complexes on the DNA.

Explain the Genetic Process Occurring in a Puff

The genetic process that occurs in a puff of a polytene chromosome is gene expression. It is a process in which genetic information in a gene (DNA) is transcribed into messenger RNA (mRNA) and subsequently translated into functional proteins. Puffs indicate regions where transcription is active, and genes are being expressed, producing specific RNAs for cellular functions such as protein synthesis or other cellular processes. In conclusion, the genetic process occurring in a puff of a polytene chromosome is gene expression. The puff represents an area of active transcription and translation, where genetic information in the DNA is being converted into functional proteins to support various cellular processes.