The Path to De-Extinction
In 2012, the world was introduced to the realm of endless possibilities opened by the DNA modification technology known as CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats). Now, in 2019, the fantasy that was Jurassic Park is looking to become a reality. While we may still be far from theme parks full of dinosaurs, scientists are treading their first careful steps on the path to the revival of extinct species. From pigeons to pachyderms, scientists at the Revive & Restore project are using molecular tools, like high-purity plasmids and CRISPR technology, in tandem with clever breeding and even more clever science to begin the restoration of some of Earth’s most recent extinct species.
The process of reviving an extinct species doesn’t start in the lab. In fact, the first and most important step of the revival project is the fieldwork. Before any gene editing can be done, scientists must know what genes they need to edit into an organism’s genome to recover the extinct sequences. For organisms such as the passenger pigeon, this is a relatively straightforward process, having only gone extinct 100 years ago and samples are readily available. Mammoths, on the other hand, have been extinct for thousands of years.
As with any scientific endeavor, the quality of a product is only as good as the quality of the input material, and many thousands of years-old samples may be severely degraded. This necessity has led to teams of ‘mammoth hunters’ who stalk the far corners of Siberia, looking for preserved mammoth corpses in the thawing permafrost. While this is a massive undertaking, it has actually yielded promising results, with hunters recently finding a mostly complete carcass of a mammoth, blood, tusks, and all.
Solving a Jigsaw Puzzle
Once scientists have the raw sequence data, they need to put back together the mammoth genome by incorporating the information into forming a living animal. While building a multicellular creature from scratch is still to be demonstrated, researchers at Revive & Restore have begun with the next best thing - modification of the Asian elephant. This animal is the closest extant relative of the Woolly Mammoth which is a critical step in bypassing de novo creation of a multicellular organism. The reason the Asian elephant is such a good model for this work is that, as the closest living relative of the Woolly Mammoth, it already shares a significant portion of its genetic makeup with the Mammoth. This way the scientists can focus on the genes that made the Mammoth distinct, rather than incorporating sequences already present in extant animals.
This effort begs the question: why bring back this species in the first place? While the endeavor to revive extinct species is a noble one, some people might ask what the purpose is when there are so many other pressing issues in the world right now, including the conservation of endangered species. But the resurrection of the Woolly Mammoth won’t just be a feat for science, it will also help with pressing issues related to climate change.
Through incorporating the genes found in the Woolly Mammoth genome into that of the Asian elephant, scientists hope to create a hybrid animal similar enough to the original species to bring back the ecological effects that the Mammoth’s presence brought upon the Earth. Once upon a time, the Woolly Mammoth roamed the frozen tundras of the world, grazing on shrubs and grass that grew through the permafrost. Without these grazing animals, these shrubs are growing without censure, causing the permafrost to melt. The goal of these researchers is to help combat climate change through the re-introduction of this species to Siberia. Scientists hope that the reintroduction of this grazing mammal to traditionally hostile environments such as Siberia will help fight the overgrowth of shrubs and reverse the thawing of the permafrost.
All of this is just the beginning of humanity’s foray into the revival of extinct species. With the mammoth project well underway, Revive & Restore has begun to investigate using this technology to save endangered species such as the Horseshoe Crab and the Black-Footed Ferret, and reviving extinct species such as the Heath Hen and Passenger Pigeon. These scientists are driven by the ecological benefits of preserving and restoring the world’s endangered and extinct species, and hope to use technologies such as CRISPR to help strive for greater conservation of the world’s species. The revival of the Woolly Mammoth represents an important first step, and proof of concept, of the potential of these technologies in ecology and conservation.
1. Marcus, A. D. (2018, October 11). Meet the Scientists Bringing Extinct Species Back from the Dead. Retrieved August 1, 2019, from The Wall Street Journal: https://www.wsj.com/articles/meet-the-scientists-bringing-extinct-species-back-from-the-dead-1539093600
2.Pruitt, S. (2019, January 22). Are Scientists on the Verge of Resurrecting the Woolly Mammoth? Retrieved July 30, 2019, from History.com: https://www.history.com/news/wooly-mammoth-resurrection-cloning-genesis
2. Revive & Restore. (n.d.). Woolly Mammoth Revival. Retrieved August 1, 2019, from Revive & Restore: https://reviverestore.org/projects/woolly-mammoth/