Gene Editing: What are CRISPR and TALEN

This is a lay description of what CRISPR and TALEN, so if you are a plant geneticist please correct me if I make any mistakes.   Both CRISPR and TALEN are gene editing techniques - they differ in their approach as to how the genes are edited.  CRISPR has been used more widely in research around biomedicine and human DNA, but TALEN has been used in the agricultural space.  While gene editing is relatively easy compared to previous techniques, its still complicated.  In the wheat genome the DNA is replicated 6 times and has 17 billion bases.

So, here are just the basics of the two techniques and some links to TED talks at the bottom if you want to learn more.


  • C - Clustered
  • R - Regularly
  • I - Interspaced
  • S - Short
  • P - Palindromic
  • R - Repeats

CRISPR uses the CAS9 protein to attach the RNA that basically cuts the very specific DNA sequence for a specific trait.  It can be so precise it can edit a single base letter in the DNA sequence.


  • T - Transcription
  • A - Activator
  • L - Like
  • E - Effector
  • N - Nucleases 

TALEN is considered easier to create a double stranded break, but because it requires a custom protein rather than an RNA sequence it is considered slower to develop than the CRISPR technique.

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In 2014 patent rights to CRISPR were contested making patent rights by companies filing for patents for products created using CRISPR challenging, especially in Europe where ownership of the intellectual property is more complex.  Calyxt is using TALEN technology in the development of its new gene edited seeds.  While Calyxt is focusing on crops, these same technologies are also being applied to animals.  Pigs for example have been genetically edited to remove a gene that causes disease.  These same technologies are also being applied to humans, and biomedicine.

If you enjoy TED talks and you want to learn more, there are some great ones about gene editing.  Here are links to a few of them..