CRISPR and Genome Editing (Part 1)

Hello friends!

I will be embarking on a 10+ part post series summarizing current research on Genome Editing and CRISPR. Then I will be moving onto its applications in various diseases such as Cancer. The first few posts will be my summary of research articles that came out in the past few years to get readers caught up (its recommended that readers are somewhat learned in Biology) to present in regards to this technology. I will explain this to the best of my ability and if I make any errors, please correct me by commenting below.


Genome Editing Vocabulary to Know for this post:

  • Genome – An organism’s complete set of DNA, organized into chromosomes in the Cell Nucleus
  • Nuclease – An enzyme that breaks DNA into smaller components
  • Homologous Recombination – a type of genetic recombination where DNA nucleotides are exchanged between similar strands
  • STEM Cells – Cells that haven’t differentiated to do a specific job
  • Short Interfering RNA (siRNA) – A type of RNA that has around 25 nucleotides and functions as an inhibitor of translation by degrading RNA after transcription
  • Transcription – The process by which DNA makes mRNA
  • Translation – The process by which mRNA encodes for specific amino acid chains (proteins) that go onto perform for the body
  • Antisense Therapy – A type of therapy for diseases that involves the making of strands of DNA to inhibit specific mRNA nucleotides from expressing

Post 1: Before Advanced Gene Editing Technology

Before advanced gene editing technologies, it was common to use homologous recombination akin to what is used in the phylum bacteria. Mice were used extensively as test subjects. It took up to 1 year to complete the process in mice.

In humans, this is much more complicated due to the fact that we are very advanced animals and eukaryotes (like mice). New methods had to be developed.

One such method was Antisense Therapy (see above for definition). Antisense Oligonucleotides (the actual DNA fragments) were used in this therapy and currently research is ongoing about drugs made from these substances. However, widespread medical use has been difficult due to the tiny scales.

Another method was to use siRNA (see above for definition). After their discovery in 1999, there was much research effort put into it to see if siRNA drugs could be effective. The main problem with both siRNA and Antisense Oligonucleotides was that both were victim to off-targeting which can significantly effect the expression of other genes, causing numerous problems.

In the 2000s and 2010s a large wave of research and technology came out to address these problems. Enter Genomic Engineering and Gene editing. The aim of these technologies was to accurately and efficiently change the genome in mammalian cells. Some technologies we will cover in later posts:

  • Zinc Finger Nucleases
  • transcription activator-like effectors (TALEs)
  • CRISPR-Cas9

  • Modern Human Genome Editing Techniques


If you like this kind of content please let me know!

If you have a comment please leave one down below!

-Sai Rachakonda,

Co-President of STEMTalksNC

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