Genome Editing Human Embryos

It seems that the ethical buzz was coming from a paper by a unknown Chinese group not involved with any of the genome editing pioneers. They took the unviable leftovers from In Vitro Fertilization (IVF) and then genome edited these human ’embyros’.

Interestingly, the success was quite poor. There was:

  • A Low Editing Rate
  • Toxicity
  • Rampant Off-Target effects

This in stark contrast to the use of CRISPR/Cas9 in dozens of animals ranging the entire tree of life. Ultimately, it doesn’t appear to be human limitation, as mammals including monkeys have been done much more successfully, but rather a result of poor experimental design, as these effects can be almost entirely attenuated by good guide RNA design and it seems that they didn’t considers the different chromatin states of embroynic stem cells that would influence off-target effects.

This was probably due to rushing the design in order to claim to be the first to alter human embryos, as opposed to the much more informative, well done, and ethically appeasing altering of Human Embryonic Stem Cells (HESCs) that showed off human CRISPR/Cas9 genome editing can be done properly in germ-line cells, with all its perks, and lead to breakthrough at the basic level in addition to all the clinical potential of genome editing technologies.

This speculation is apparent as there was a large outcry when the Chinese authors tried the ‘high impact’ journals and it seems they settled on a much lesser known open access that has additional concerns with the peer review process, mainly that it took one day, instead of 6 months to a year of the purgatory that is usually is.

Ultimately, it seems this was rushed for fame of unknown researchers and unknown journal, rather than science. But it’s still a Pubmed indexed journal with an impact factor and published by Springer. It is a bit of a shame as the Pandora’s box of CRISPR in human embryos needed to be opened quite slowly and carefully. The parts are all relatively easily accessible and not restricted, which is what has lead to spectacular pace of CRISPR/Cas9 genome editing development. While the field has its leaders developing CRISPR for the clinic the proper way, the technology it is now at the place where it can be picked up by many more who may not just be interested in the somatic line. But here we are now, waiting to see if genome editing technology will change the world, by curing inherited human disease or being used to design sci-fi nightmares. Either way, human inheritance has entered the designer era.


  1. The Primary Publication
  2. Nature News
  3. Stem Cell Assays

A Scientific Landmark: Inherited and Efficient Genome Editing of Human Embryos

With scientists a buzz, it seems that the dreams of sci-fi have become sic-fact. Apparently, papers are circulating where human embryos have been edited (but not taken to term):

“There are also suspicions that scientists have already created human embryos with edited genomes. Several researchers who do not want to be named told Nature’s news team that papers describing such work are being considered for publication.”

Source: Nature News

My suspicions of the players involved in the work or bringing it to public attention are some of the big 4 of (epi)genome editing: Feng Zhang, Jennifer Doudna, J. Keith Joung, and George Church. I think there is a good chance that George Church and army were involved somehow based on this recent interview with the MIT Technology Review.

It seems like the community doesn’t know what to think of the possibility as it came much early then most would have dreamed. The ability to alter simple Mendelian traits would have tremendous implications for inherited disease. Although, the off-target effects have been greatly improved from previous technologies, they are still there and concerning, but it may not be enough to stop some. Sure we’ve been able to create mutations before, but never with such accuracy, ease, precision, and potential for successful pregnancy with in vitro fertilization in a HUMAN. If it happens, I don’t think anyone would be able to consider the initial experimental optimization ethical.

Then again, this all just rumours and buzz with a bit conjecture. I’m quite curious to see the actual work and the levels of success achieved in the editing of embryos.