The Ethics of Gene Editing (Download PDF)

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World Health Organization is creating working group to study gene editing & complex ethical, social & safety issues procedure raises. Gene-editing system called Crispr-Cas9 or Crispr is simple, cheap & effective.

Image of Gene editing

Image of Gene Editing

Image of Gene editing

  • Panel will help develop agreed norms & standards for governance of human gene editing.

  • Gene-editing system called Crispr-Cas9 or Crispr is simple, cheap & effective.

  • It promises to change human relationship w/genetics for better, worse or both.

  • Its champions foresee using Crispr to control pests, increase food production & eliminate human diseases.

The Situation That Led to Ethical Concerns with Gene Editing

  • The announcement comes one week after Chinese scientist claimed to have created world’s 1st gene-edited babies.

  • He used Crispr to alter genes of pair of twins while they were embryos to make babies resistant to HIV, virus that causes AIDS.

  • Using Crispr to make changes to embryos & germline cells: sperm, eggs & zygotes is especially contentious because modifications are passed to progeny.

  • U. S. science & medicine advisory group in 2017 decided to support research using technologies like Crispr to modify human embryos for prevention of serious diseases & disabilities.

  • Labs are using Crispr to experiment w/germline modifications. These include killing off malaria-carrying mosquitoes, making wheat invulnerable to blight of powdery mildew, producing eggs suitable for people allergic to them & bringing woolly mammoth back from extinction.

  • Researchers have used Crispr w/human cells to repair mutation that causes blindness & correct defect responsible for cystic fibrosis.

  • 1st human trial began in China in 2016 using Crispr-modified T-cells to treat lung-cancer patients.

  • In late 2018, trial in Europe began recruiting volunteers w/blood disorders sickle-cell anemia & beta thalassemia.

  • 2 studies published in mid-2018 found that cells edited by Crispr have potential to seed tumors, raising risk that they’d trigger cancer, but link is still under investigation.

What is Gene Editing?

  • Genome editing (called gene editing) is group of technologies that give scientists ability to change organism’s DNA.

  • These technologies allow genetic material to be added, removed, or altered at particular locations in genome.

  • Recent approach to genome editing is known as CRISPR-Cas9, which is short for clustered regularly interspaced short palindromic repeats & CRISPR-associated protein 9.

  • CRISPR-Cas9 was adapted from naturally occurring genome editing system in bacteria.

  • Bacteria capture snippets of DNA from invading viruses & use them to create DNA segments known as CRISPR arrays.

  • CRISPR arrays allow bacteria to “remember” viruses (or closely related ones). If viruses attack again, bacteria produce RNA segments from CRISPR arrays to target viruses’ DNA. Bacteria then use Cas9 or similar enzyme to cut DNA apart, which disables virus.

  • Researchers create small piece of RNA w/short “guide” sequence that attaches (binds) to specific target sequence of DNA in genome.

  • RNA binds to Cas9 enzyme. As in bacteria, modified RNA is used to recognize DNA sequence, & Cas9 enzyme cuts DNA at targeted location.

  • Once DNA is cut, researchers use cell’s own DNA repair machinery to add or delete pieces of genetic material, or to make changes to DNA by replacing existing segment w/customized DNA sequence.

  • Genome editing is of great interest in prevention & treatment of human diseases.

  • It is being explored in research on wide variety of diseases, including single-gene disorders like cystic fibrosis, hemophilia & sickle cell disease.

  • It promises for treatment & prevention of more complex diseases, such as cancer, heart disease, mental illness & HIV infection.

- Published/Last Modified on: January 15, 2019

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