Geneticist George Church is working to resurrect the woolly mammoth that went extinct 4,000 years ago.
Colossal Biosciences is a startup founded by tech entrepreneur Ben Lamm and renowned geneticist George Church, aiming to bring back the woolly mammoth, or more accurately, to create a genetically modified Asian elephant that can withstand cold and possesses all the key biological traits of its extinct relative. In mid-August 2022, the company also announced plans to bring back the Tasmanian tiger.
Although it will not be an exact replica, the hybrid animal will resemble the woolly mammoth and could inhabit the same ecosystem where the extinct elephants once roamed. The scientific aspect of this ambitious and controversial project is led by Church, as reported by Newsweek on August 21. His pioneering research has contributed to the development of DNA sequencing technology and genetic editing.
Church directs synthetic biology research at the Wyss Institute for Biologically Inspired Engineering at Harvard University. He is also a professor of genetics at Harvard Medical School and holds several positions at the Massachusetts Institute of Technology (MIT) and various other institutes. He has co-authored hundreds of scientific papers and holds dozens of patents, having co-founded more than 20 companies. For a long time, he has dreamed of bringing the woolly mammoth back to life. After collaborating with Lamm, that dream may become a reality, though it initially requires overcoming significant scientific and logistical challenges.
The appearance of the ancient woolly mammoth. (Photo: iStock)
Gene Editing Steps
Colossal’s goal is to create a hybrid elephant with characteristics of the woolly mammoth, such as thick fur and layers of fat, along with other adaptations for cold climates. They will use advanced gene editing technology. According to Church, this method is quite similar to research conducted by one of his companies on pigs. In that study, scientists performed about 40 edits to the pigs’ genome to make their organs suitable for transplantation into humans.
Colossal plans to carry out a similar number of edits on cells taken from Asian elephants, an endangered species that is the closest living relative of the woolly mammoth, sharing about 99.6% of their genome. In fact, Asian elephants and woolly mammoths are more closely related to each other than to African elephants, Church noted.
To determine which edits are necessary, Colossal’s research team needs to compare the genomes of Asian elephants with those of woolly mammoths to identify key differences. Some mammoth remains have been exceptionally well-preserved, with tissue samples still containing intact DNA. From there, researchers can reconstruct at least part of the genome. They can then begin editing genes in cells taken from Asian elephants with the aim of creating an animal that resembles a mammoth more closely. The number of edits will be approximately the same as in the previous pig genome study.
“We will use CRISPR or various other editing tools to modify the cells by adding DNA. Next, we will separate the nucleus from the cell and place it into an egg. We will implant it into a surrogate mother and wait. In the case of elephants, that is 22 months. The result is a calf. The challenge is not in resurrecting a species but in reviving individual genes in a cluster, aiding cold tolerance,” Church said.
Artificial Womb or Surrogacy
Another method that Colossal’s team is researching in parallel is the development of a hybrid embryo of Asian elephants and woolly mammoths in an artificial womb instead of using a surrogate mother. The surrogate mother is likely to be an African elephant rather than an Asian elephant due to the former’s larger size, which would make it easier to give birth to a hybrid elephant.
This has never been done before with any mammal, but researchers have achieved success with some species. For example, a team of experts at the Children’s Hospital of Philadelphia once nurtured sheep embryos for 4 weeks. The newborn lambs typically weigh over 90 kg at birth.
While using a surrogate mother is more feasible due to technology being validated to some extent with other mammals, Church noted that most team members support the artificial womb method despite the technical challenges, as it could scale up and not impact the reproduction of living elephants. Colossal’s goal is to create a viable Asian elephant-woolly mammoth hybrid within six years.
Environmental Benefits
If Colossal achieves its goal, the company hopes to introduce enough elephants into the wild to restore the health of the Arctic environment and slow the melting of permafrost, preventing the release of massive amounts of greenhouse gases that threaten climate change mitigation efforts.
The woolly mammoth was a keystone species that played a crucial role in maintaining the health and biodiversity of the ecosystem in which it lived. The disappearance of the woolly mammoth over the past few thousand years has contributed to a decline in carbon-absorbing grasslands in the Arctic. Today, this ecosystem is dominated by moss forests and wetlands.
Restoring grasslands could help prevent thawing and the release of greenhouse gases from permafrost in the polar regions, according to Colossal. An additional effect that Church and his colleagues are interested in is maintaining the soil in the Arctic by allowing elephants to trample snow and introduce cold air into the ground during winter.
Moreover, grasslands also reflect sunlight better than the current trees in the Arctic due to their lighter color. Therefore, the more grassland there is, the more it helps cool the ecosystem. According to Church, Colossal is focusing on areas in the Arctic with the highest carbon levels because more methane, a potent greenhouse gas, will be released if permafrost in those areas melts.
If Colossal can create the Asian elephant-woolly mammoth hybrid, their plan is to introduce tens of thousands of them to the Arctic at a density of one per square kilometer. They believe that this number is sufficient to create an impact, such as preventing methane release. Colossal will build several centers with incubators at the center. Herds of elephants will radiate from there. However, the timeline to reach that number will be extremely long if reproduction requires female elephants to act as surrogates.
