How Will CRISPR Help in De-Extinction?

De-extinction—the concept of bringing back extinct species—has transitioned from science fiction to an ambitious scientific endeavor. CRISPR, a groundbreaking gene-editing technology, is at the heart of this movement. But how does CRISPR work, and what role does it play in de-extinction? This Q&A explores the science, applications, and progress in this field.*

Q: What is CRISPR, and how does it work?

A: CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a revolutionary gene-editing tool derived from a bacterial defense system. It allows scientists to precisely edit DNA by targeting specific sequences. Using a guide RNA (gRNA) to locate the DNA sequence of interest, CRISPR’s associated enzyme, usually Cas9, cuts the DNA at the targeted site. This cut can then be repaired by the cell, enabling the insertion, deletion, or alteration of genetic material.

Q: How is CRISPR applied to de-extinction projects?

A: CRISPR is used in de-extinction to edit the genomes of living species closely related to extinct ones. For example:

1. Identifying and Extracting DNA: Scientists extract DNA fragments from well-preserved remains of extinct species. While this DNA is often incomplete or degraded, advanced sequencing techniques help reconstruct significant portions of the genome.
2. Editing Closely Related Species: Once the genome of the extinct species is mapped, CRISPR can be used to edit the DNA of a closely related living species. For instance, genes unique to the extinct species are introduced into the living species’ genome.
3. Creating Hybrid Embryos: The edited DNA can be used to create embryos that exhibit traits of the extinct species. These embryos are then implanted into surrogate mothers or developed using artificial wombs.

Q: What species are currently being targeted for de-extinction using CRISPR?

A: Several high-profile de-extinction projects are underway:

• Woolly Mammoth Colossal Biosciences aims to bring back the woolly mammoth by editing the DNA of Asian elephants, their closest living relatives. The project focuses on reintroducing traits like cold resistance by integrating mammoth genes.
• Tasmanian Tiger (Thylacine): Researchers, also, from Colossal Biosciences are working on editing the genome of the dunnart, a small marsupial, to reintroduce genes from the Tasmanian tiger.
• Dodo: Colossal Biosciences is also working to bring back the dodo, an extinct flightless bird. By editing the genome of the Nicobar pigeon, the dodo’s closest living relative, scientists aim to recreate the bird’s unique characteristics and reintroduce it into its historical habitat.

Q: What challenges arise with CRISPR and de-extinction?

A: While promising, de-extinction projects face several hurdles including the fact that perfectly reconstructing extinct genomes is challenging due to DNA degradation over time, and gaps in the genetic information can complicate efforts to faithfully recreate extinct species.

Q: What advancements have been made by Colossal Biosciences and other teams?

A: Among the many advancements by Colossal Biosciences includes… 

• Woolly Mammoth Project: They’ve successfully identified and edited genes responsible for traits like thick fur and fat storage, a crucial step toward creating hybrid embryos that can survive in Arctic environments. Additionally the team has created elephant iPSCs and a cure for elephant herpes. 
• Dodo Revival: The company has initiated efforts to bring back the dodo by mapping its genome and editing the DNA of the Nicobar pigeon, aiming to recreate the bird’s unique traits and potentially reintroduce it to its native habitats.
• Tasmanian Tiger: Advances in editing marsupial genomes have allowed for greater progress in the effort to revive the Tasmanian tiger, using the dunnart as a surrogate species.
• Collaborative Efforts: The company partners with conservation organizations, geneticists, and universities to develop cutting-edge technologies for genome editing, artificial wombs, and species restoration. These partnerships accelerate research and open up possibilities for broader ecological applications.

Other teams, such as Revive & Restore, focus on combining CRISPR with conservation strategies to protect endangered species and lay groundwork for de-extinction.

Q: What does the future hold for CRISPR and de-extinction?

A: As CRISPR technology advances, the possibilities for de-extinction expand. Enhanced precision, cost reductions, and improved understanding of genomes will accelerate the scientific  progress. Beyond de-extinction, these developments could revolutionize conservation, medicine, and agriculture.

De-extinction remains an ambitious goal, but CRISPR provides the tools to turn vision into reality, offering a glimpse into a future where extinct species walk the Earth once more.