Germ-line: “To edit or not?”

“Knowledge without wisdom is like an unsaddled horse” Zen Master

Since the 1970s, the saga of “rDNA technology” has been a steady narrative. In this 40 years of development and evolution, gene editing techniques have become more and more easier and accessible. CRISPR-Cas9 system testifies to this fact. And time after time, every turn of gene editing advancement has witnessed sharp ethical questions fencing its signs.

Rightly so, it should! especially when technologies bare opens the possibility of creating heritable mutations, answers to ethical questions becomes an entitlement.

As I write this post, The US National Academy of Science, Engineering, and Medicine, along with British Royal Society and Chinese Academy of Sciences are co-sponsoring an international summit (in Washington, DC, USA from December 1st -3rd, 2015) to debate and discuss the scientific and societal implications of germ-line genome editing.

Clusterd regularly interspaced pallindromic repeats (CRISPR)-Cas9 system:

About CRISPR-Cas9 technology: 

CRISPR-Cas9 genome editing takes advantage of a prokaryotic acquired immune system. The simplicity of this technology gives the power to alter genomes precisely than ever before. With this system, we could replicate the genetic basis for human diseases in model organisms and scientists can gain insights into the mysterious and puzzling disorders, that was not possible earlier. The technology can be used to correct genetic defects in whole animals as well as in tissues cultured from stem cells. A strategy that has the potential to be eventually used to treat or cure human diseases. The Cas9 enzyme also has the ability to alter epigenetic markers without altering the DNA code, providing a means to manipulate the products of transcription.

Germ-line editing:

DSC_0024_edit_it.71857f089e564c7399626b5977cfb7a7Genome editing in a non productive and fully developed cell have effect only on the treated organism or person (which is not heritable). However, gene editing in germ cells such as that in eggs, sperms or developing embryos can be passed on to the future generations. CRISPR-Cas9 system has the ability to be used in both non productive as well as germ cells (germ-line). And the fact that scientists from Sun Yat-sen University in Guangzhou, China edited human embryos (P. Liang et al., Protein Cell 6, 363-372; 2015) shows that this technology has profound implications for germ-line editing and raises the urgent need to address the social and ethical concerns.

Different voices:

A range of voices, that favor the advancement to outright banning of the technology for foreseeable future can be heard within the scientific community.

 “Encourage the innovators.  says George Church (Geneticist, Harvard Medical School), one of the favoring voices “Banning human germ-line editing could put damper on the best medical research, driving the practice underground” is his argument. Moderate voice such as Jennifer Doudna (Molecular biologist, University of California) suggest Embryo editing needs scrutiny. and reason that “a complete ban is impractical, given the widespread accessibility and ease of use of CRISPR-Cas9.” Thus, favoring formulation of guidelines for use of the technology.

Scientific research is important in understanding complex genetic diseases. When it comes to creating heritable mutations with editing technologies, it is a fact that we do not know enough about many of the effects (both on and off-target) and its limitations. Complete banning would further limit our understanding. It is here as scientists that we have to tread carefully. Hopefully, the international summit will act as a primer for formulation of guidelines in human germ-line editing.

In agreeing with Jennifer Doudna, formulating guidelines that address

  1. Safety (of the technology),
  2. Communication (with engaging scientific community, ethical bodies and general public),
  3. Guidelines (policy makers and scientists)
  4. Regulation (efficacy and specificity) and
  5. Caution (human germ-line editing for creating genome modified humans should not proceed at this time)

will be key for a progressive way forward.


Doudna, J. A. (2015). PERSPECTIVE: Embryo editing needs scrutiny. Nature, 528, S6.

Church, G. (2015). PERSPECTIVE: Encourage the innovators. Nature, 528, S7.

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