What does polytene mean?
: relating to, being, or having chromosomes each of which consists of many strands with the corresponding chromomeres in contact.
How does a polytene chromosome differ from a typical eukaryotic chromosome?
How does a polytene chromosome differ from a typical eukaryotic chromosome? … A polytene chromosome contains banding patterns and is large because of repeated replications of DNA without nuclear division. Although mutations have been observed in many different genes, they have not been isolated in histones.
Do humans have polytene chromosomes?
While polytene chromosomes are most frequently found in insects, they are critical in diverse organisms from ciliates to plants to humans, and they play important roles in disease progression.
What are polytene and Lampbrush chromosomes?
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.
Are polytene chromosomes haploid or diploid?
The end product of the replication cycles is a nucleus with a haploid number of chromosomes, each containing up to 2,000 or more parallel strands. In the Collembola, however, the polytene chromosomes typically remain unpaired and the nuclei contain the diploid number (Fig. 92).
Do polytene chromosomes show somatic pairing?
In salivary gland chromosomes/polytene chromosomes, pairing is formed between homologous chromosomes. A characteristics feature of these chromosomes is that somatic pairing occurs in them and hence their number appears half of normal somatic cells.
What are puffs in polytene chromosomes?
Puffing is the term that describes structural changes in polytene chromosomes. If one observes polytene chromosomes during the late prepupal stage, different bands appear to be puffed up. For 40 years, this has been understood to be the result of gene activity.