Dear Readers, New Scientist this week has an article about ‘de-extinction’ – the process whereby scientists are attempting to bring back extinct species, using a combination of genetic editing, cloning and surrogacy. The most famous project is probably that of Colossal, a biosciences company that wants to recreate the woolly mammoth, and the TIGGR project at the University of Melbourne which wants to resurrect the thylacine or Tasmanian Tiger. Restore and Revive, a US NGO, is trying to de-extinct the passenger pigeon and the heath hen. But a study by the University of Copenhagen has shown up some of the difficulties in trying to bring back an extinct species from the dead (and that’s before we even get on to the ethical questions).
Thomas Gilbert at the University of Copenhagen has been working with a team who are looking at the Christmas Island Rat, also known as Maclear’s Rat (Rattus macleari). This rodent became extinct in the early 20th century, and a high-quality genome was extracted from preserved specimens. However, there were still many gaps in the genome, some of which could be filled by looking at the genes of the closely-related brown rat, but there was still a gap of some 5% of the genome, and the scientists have no idea what it did.
Crucially, it’s these genes that were the most recent, and which made the difference between the Christmas Island rat and the brown rat. It’s thought that in this case the missing genes relate to the rat’s immune system, and to its sense of smell – the latter, in particular, would influence the way that the Christmas Island rat found its food, interacted with other rats, and avoided predators. So, even if a ‘Christmas Island Rat Mark II’ could be created that looked like the original species, its behaviour is still likely to be very different.
Still, the companies that have set their hearts on recreating extinct animals soldier on in the face of ethical opposition. Just to set out my personal stall on the subject, it seems that the money being invested in de-extinction could be better spent on preserving habitats for the elephants, marsupials and birds that are in danger of extinction, rather than bringing back those who have already gone. Of course, that doesn’t mean that all this investment would go to these causes (just as the money spent on the space race wouldn’t have gone to ending world hunger if we’d never gone to the moon) but I smell a distinct whiff of the profit motive in many of these de-extinction projects. How much would people pay to see mammoths roaming in an American safari park, I wonder? And how much would these animals sell for?
Furthermore, many of these animals, especially the mammoths and passenger pigeons were intensely social creatures – how many are the companies actually planning to recreate, or is this a case of a few sad specimens in some kind of zoo? And what about the female elephants who would be the surrogates for the calves who are created, in the case of the mammoths?
All this for an animal that is probably just a poor facsimile of the original species, from a habitat that is now largely gone or degraded.
It is, of course, possible that interesting discoveries might be made in the search to revive these animals, discoveries that could be beneficial for living animals. But on balance, I think that just because we can do something, even imperfectly, it doesn’t mean that we should. Let’s try to preserve what we have, and what we are in danger of losing.
You can read the full article here.
Photo One By Thomas Quine – https://www.flickr.com/photos/quinet/44598416660/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=80400437
Photo Two By Joseph Smit – Proceedings of the Zoological Society of London 1887 web, Public Domain, https://commons.wikimedia.org/w/index.php?curid=15135055