What is main features of Lampbrush chromosomes?
What is main features of Lampbrush chromosomes?
They are highly extended meiotic half-bivalents, each consisting of 2 sister chromatids. Lampbrush chromosomes are clearly visible even in the light microscope, where they are seen to be organized into a series of chromomeres with large chromatin loops extended laterally.
Why are the structures called Lampbrush chromosomes?
Lampbrush Chromosomes (LBCs) are present in the oocytes of birds, lower vertebrata and invertebrates during the prolonged prophase of the first meiotic division. Their name stems from their similarity to bottle brushes. Lampbrush chromosome of the early prophase is a bivalent, made up of two conjugating homologues.
What is the function of Lampbrush chromosomes?
Lampbrush chromosomes are also involved in the production of “masked” mRNAs for early development. The giant granular loops could either be the sites where such mRNAs are packaged or they could be sites where specific alterations of the deoxyribonucleoprotein fiber take place.
What is Lampbrush and polytene 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.
Why lampbrush chromosomes are absent in mammals?
Answer :- Human and other mammalian chromosomes do not form recognizable lampbrush chromosomes in their own oocytes or in any somatic cells.
What is the size of Lampbrush chromosome?
We describe methods for studying the giant transcriptionally active lampbrush chromosomes (LBCs) found in the oocyte, or unlaid egg, of frogs and salamanders. Individual LBCs can be up to 1 mm in length and they reside in a gigantic nucleus, itself up to 0.5 mm in diameter.
Where is Lampbrush chromosome found?
oocytes
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.
Which is largest chromosome Lampbrush or polytene?
[II] Polytene chromosomes: These are also giant chromosomes but relatively smaller than lampbrush chromosomes, found in the larvae of certain dipterans.
Do humans have lampbrush chromosomes?
Human and other mammalian chromosomes do not form recognizable lampbrush chromosomes in their own oocytes or in any somatic cells.
Do humans have Lampbrush chromosome?
