Your question: What are special chromosomes?

What are the special chromosomes?

The types are: 1. Polytene Chromsomes or Salivary Gland Chromosomes 2. Lampbrush Chromosomes 3. Prokaryotic Nucleoids.

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.

What are the 4 types of chromosomes?

Chromosomes can be classified into 4 types based on the length of the chromosomal arms and the position of the centromere.

  • Sub metacentric chromosomes.
  • Acrocentric chromosomes.
  • Telocentric chromosomes.
  • Metacentric chromosomes.

What is special about the polytene chromosome?

Polytene chromosomes, at interphase, are seen to have distinct thick and thin banding patterns. These patterns were originally used to help map chromosomes, identify small chromosome mutations, and in taxonomic identification. They are now used to study the function of genes in transcription.

Is Lampbrush a 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.

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What is types of chromosomes?

Human chromosomes

Chromosomes in humans can be divided into two types: autosomes (body chromosome(s)) and allosome (sex chromosome(s)). Certain genetic traits are linked to a person’s sex and are passed on through the sex chromosomes. The autosomes contain the rest of the genetic hereditary information.

What do you mean by 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.

What is the function of Lampbrush chromosome?

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 the significance 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.

What are the 3 types of chromosome?

On the basis of the location of the centromere, chromosomes are classified into four types: metacentric, submetacentric, acrocentric, and telocentric.

What are the 2 main types of chromosomes?

Among many organisms that have separate sexes, there are two basic types of chromosomes: sex chromosomes and autosomes. Autosomes control the inheritance of all the characteristics except the sex-linked ones, which are controlled by the sex chromosomes. Humans have 22 pairs of autosomes and one pair of sex chromosomes.

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Which type of chromosome is absent in human?

The absence of Y chromosome in human beings causes .

What is salivary chromosome?

Definition of salivary chromosome

: one of the very large polytene chromosomal strands made up of many chromatids that are typical of the salivary gland cells of various insects.

What does Polytene mean?

Definition of polytene

: relating to, being, or having chromosomes each of which consists of many strands with the corresponding chromomeres in contact.

What is a puff on a polytene chromosome?

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.