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Circadian Rhythms and Gene Regulation02:19

Circadian Rhythms and Gene Regulation

The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
Circadian Rhythms and Gene Regulation02:19

Circadian Rhythms and Gene Regulation

The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
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In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).Mechanisms of Genetic VariationThe original sources of genetic variation are mutations,...
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Sequencing of the human genome has opened up several best-kept secrets of the genome. Scientists have identified thousands of genome variations that exist within a population. These variations can be a single nucleotide or a larger chromosomal variation.
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Detection and Monitoring of Tumor Associated Circulating DNA in Patient Biofluids
06:53

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Published on: June 8, 2019

Circulating DNA. Its origin and fluctuation.

Maniesh van der Vaart1, Piet J Pretorius

  • 1School of Biochemistry, North-West University, Potchefstroom Campus, Potchefstroom, South Africa.

Annals of the New York Academy of Sciences
|October 8, 2008
PubMed
Summary
This summary is machine-generated.

Circulating DNA levels rise in various diseases, but apoptosis or necrosis aren't the main source. Evidence suggests living cells actively release this DNA, with imbalances in release and clearance driving elevated levels.

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Area of Science:

  • Biochemistry
  • Molecular Biology
  • Genetics

Background:

  • Circulating DNA fragments are found in blood, with elevated levels observed in cancer and other conditions.
  • The precise origin of these circulating DNA fragments remains unclear despite decades of research.
  • Current understanding often attributes circulating DNA to cell death processes like apoptosis and necrosis.

Purpose of the Study:

  • To investigate the primary source of circulating free DNA in the bloodstream.
  • To challenge the prevailing hypothesis that apoptosis or necrosis are the main contributors to circulating DNA.
  • To explore alternative mechanisms for the release of circulating DNA by cells.

Main Methods:

  • Analysis of existing research and evidence regarding the origin of circulating DNA.
  • Evaluation of the role of apoptosis and necrosis in circulating DNA release.
  • Consideration of active DNA release mechanisms by living cells.

Main Results:

  • Evidence presented does not support apoptosis or necrosis as the major source of circulating free DNA.
  • Active release of circulating free DNA by living cells is proposed as a plausible mechanism.
  • An imbalance in the equilibrium between DNA release by living cells and clearance mechanisms may explain elevated levels.

Conclusions:

  • The origin of circulating free DNA is likely more complex than solely cell death.
  • Active release of DNA by living cells warrants further investigation as a key mechanism.
  • Understanding these release and clearance dynamics could improve the diagnostic and prognostic utility of circulating DNA.