What is Balbiani ring?

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.

Similarly, you may ask, what is the function of polytene chromosomes?

Polytene chromosomes are large chromosomes which have thousands of DNA strands. They provide a high level of function in certain tissues such as salivary glands.

Also Know, what is a chromosome puff? chromosome puff. A localised separation of polytene chromosomes (e.g., chromosomes of Drosophila melanogaster) that represents a site of active RNA synthesis—i.e., transcription—which, when very large, is known as a Balbiani ring.

Moreover, what are Polytene and Lampbrush chromosomes?

[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.

Do humans have polytene chromosomes?

Polytene chromosomes are a solution to a problem experienced by some species of flies. Humans are in a different phylum and have different problems. Humans may have stumbled into a different solution than the fruit flies did.

Where are Lampbrush chromosomes found?

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.

What is a Chromocenter?

Definition of chromocenter. : a densely staining aggregation of heterochromatic regions in the nucleus of some cells.

What are special chromosomes?

Lampbrush Chromosomes: Lampbrush chromosomes are special type of giant chromosomes found in the nuclei of oocytes of many vertebrates, such as fishes, amphibians, reptiles and birds during the prolonged diplotene stage of first meiosis. They are also found in the nucleus of Drosophila spermatocyte.

Who discovered heterochromatin?

Emil Heitz

Which is largest chromosome?

Chromosome 1

Who discovered Lampbrush chromosome?

Lampbrush chromosomes were discovered in sala- mander egg cells (Ambystoma mexicanum) by Flemming in 1882. Ten years later, LBCs were identified in shark egg cells and described by Rückert in 1982. It was Rück- ert who introduced the term “lampbrush chromosome” into biological nomenclature.

What is beta chromosome?

B chromosomes are chromosomes which are not needed for the life of a species. They are also called 'supernumerary' or 'accessory chromosomes'. In addition to normal chromosomes (the karyotype), many species have B chromosomes. Wild populations of many animal, plant, and fungi species have B chromosomes.

What are polytene chromosomes how are they formed?

Polytene chromosomes are formed by the repeated replication of homologous chromosomes, in which the replicated individual sister chromatid strands do not separate. Polytene chromosomes have approximately 1000 identical DNA molecules, which are all perfectly aligned laterally within the structure.

What are the 4 types of chromosomes?

Deoxyribonucleic acid (DNA) is the way genetic information is stored within cells and allows the transmission of information from one generation to the next. There are four main types of chromosomes: metacentric, submetacentric, acrocentric, and telocentric.

What is the function of Lampbrush chromosome?

Giant chromosomes in the lampbrush form are useful model for studying chromosome organization, genome function and gene expression during meiotic prophase, since they allow the individual transcription units to be visualized.

Which of the following is largest chromosome?

Chromosome 1 is the largest and chromosome 22 is the smallest.

What is the ploidy of polytene chromosomes?

Because the number of endocycles can vary between tissues and organisms, polytene chromosomes cover an impressive range of ploidy from those that are only reduplicated a single time to chromosomes made of many thousands or even millions of genome copies (Nagl 1978).

How many pairs of chromosomes do fruit flies have?

four

What is a puff in a polytene chromosome quizlet?

It is underwound. What is a "puff" in a polytene chromosome? the DNA double helix coiled around a histone octamer. the telomere. the centromere.

Can you now explain why one can directly observe polytene chromosomes under a conventional light microscope?

It is possible to directly observe polytene chromosomes under a conventional light microscopy as they contain multiple strands of dna that are partially uncoiled. You will also assess the impact of temperature on the initiation of confined swelling or puffing.

How are polytene chromosomes relevant to the Drosophila melanogaster life cycle?

Polytene Chromosomes As the fly larva grows, it keeps the same number of cells, but needs to make much more gene product. The result is that the cells get much bigger and each chromosome divides hundreds of times, but all the strands stay attached to each other.

Are polytene chromosomes physically interconnected?

All polytene chromosomes of Drosophila are connected at their centromeres. The centromere domains are strongly heterochromatic and are also called chromocenters. Polytene chromosomes can be recognized by their clear and regular bands, the pattern is highly specific.

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