Cell-free DNA

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In the last two decades or so, since genome sequencing technologies started to become more accessible, scientists have really figured out the application of the Cell-free DNA.

About Cell-free DNA: 


  • In the human body, most of the DNA in a genome is neatly packed inside cells with the help of specific proteins, protecting it from being degraded.
  • In a variety of scenarios, some fragments of DNA are ‘released’ from their containers and are present outside the cell, in body fluids. These small fragments of nucleic acids are widely known as cell-free DNA (cfDNA).
  • How they are generated/released?
  • It can be generated and released from a cell in a number of possible situations, including when a cell is dying and the nucleic acids become degraded.
  • Since an array of processes modulates the degradation, the amount, size, and source of the cfDNA can vary across a range as well.
  • This could occur together with a variety of processes, including those required for normal development, those related to the development of certain cancers, and those associated with several other diseases. 


Applications of cfDNA

  • One of the most widely used applications of cfDNA has been in screening foetuses for specific chromosomal abnormalities, an application known as non-invasive prenatal testing. 
  • It is useful tool to understand human diseases and to use the knowledge to improve diagnosis, monitoring, and prognosis.
  • It is useful in understanding why a body is rejecting a transplanted organ.
  • This  could be used as a biomarker for neurological disorders like Alzheimer’s disease, neuronal tumours, stroke, traumatic brain injury.


Q1) What is a biomarker?

A biomarker, short for biological marker, is a measurable and quantifiable characteristic or substance that indicates the presence or severity of a particular biological process, disease, or condition. Biomarkers can be found in various biological materials, such as blood, urine, tissue, or saliva, and they are used to assess the physiological or pathological state of an organism.

Source: Cell-free DNA promises to transform how we find diseases