Which are the two types of giant chromosome?
The types are: 1. Polytene Chromsomes or Salivary Gland Chromosomes 2. Lampbrush Chromosomes 3.
Is Lampbrush a giant chromosome?
They are about 0.5 mm in length and 20 μm in diameter. They are produced when repeated rounds of DNA replication without cell division forms a giant chromosome.
What are Polytene and lampbrush chromosomes?
There are some probabilities that lampbrush chromosomes help in the formation of certain amount of yolk material for the egg. [II] Polytene chromosomes: These are also giant chromosomes but relatively smaller than lampbrush chromosomes, found in the larvae of certain dipterans.
What are giant chromosomes give examples?
Special chromosomes include lampbrush chromosome, polytene chromosome and B chromosome. i. Lampbrush Chromosome: These are special types of chromosomes in which large number of loops are projected out from the chromatin axis giving a lampbrush appearance.
Do humans have giant chromosomes?
Polytene chromosome is found in a diverse set of insects, plants, animals, and unicellular organisms (Table 1). Polytenes can also result pathologically from perturbations in cell cycle regulation.
|Cell type||Trophoblast giant cell|
What does Polytene mean?
: relating to, being, or having chromosomes each of which consists of many strands with the corresponding chromomeres in contact.
Which is the largest chromosome?
Chromosome 1 is the largest human chromosome, spanning about 249 million DNA building blocks (base pairs) and representing approximately 8 percent of the total DNA in cells. Identifying genes on each chromosome is an active area of genetic research.
Which is larger Polytene or Lampbrush chromosome?
[II] Polytene chromosomes:
These are also giant chromosomes but relatively smaller than lampbrush chromosomes, found in the larvae of certain dipterans. … Because of their large size showing numerous strands these are named as polytene chromosomes (name suggested by Kollar) or commonly salivary gland chromosomes.
What is a Lampbrush chromosome?
Lampbrush chromosomes (LBCs) are transcriptionally active chromosomes found in the germinal vesicle (GV) of large oocytes of many vertebrate and invertebrate animals and also in the giant single-celled alga Acetabularia. These cells are all in prophase of the first meiotic division.