My best friend has nightmares about dinosaurs; T. rexes chasing and searching for her as she hides behind furniture. I don’t blame her. Courtesy of Jurassic Park, I’m sure there are plenty of others who have had similar nightmares. During my PhD, I once had a nightmare that Neanderthals were back and trying to take over Europe. But is it really possible to bring back species from the dead?
At first glance, it seems to be more difficult than the movies give credit for. In 2009, the New Scientist published an article outlining the method for any Dr Moreau wannabes, but also why the technology is not available for it to work:
1- Obtain a complete and accurate genome
2- Package and assemble this genome into chromosomes
3- Identify a suitable surrogate to provide the egg and to gestate the embryo to full term
But as technology is moving at a face pace the limits of scientific accomplishments are being further tested. Revive and Restore is a project aiming to push the boundaries for resurrecting extinct species. Inspiration for this project came when the last passenger pigeon (a species hunted to extinction for its meat) named Martha died in Cincinnati Zoo in 1914. Several species have since been chosen as candidates to be resurrected, including a range of birds, the quagga, the Easter Island palm and several Pleistocene mammals. The first meeting held on the 8 February 2012 brought together conservation biologists and geneticists to assess the feasibility of resurrection. Since then the project has established a list of criteria to examine the suitability of each candidate species, e.g. how will bringing back the species answer scientific questions, is it possible to re-wild a species and, if selecting a species further back in time, is there enough preserved DNA. Sure enough in 2013 an article What If Extinction Is Not Forever? appeared in Science discussing the risks versus the benefits. The objections fell into five categories: animal welfare, health, environment, political and moral, and the benefits included: scientific knowledge, technological advancement, environmental benefits, justice and the “cool” aspect of it.
One of the reasons why the passenger pigeon was selected is because there are plenty of samples that are young enough to obtain good quality DNA. The key issue therefore lies in the survivability of ancient DNA sequences. The potential rests firstly in obtaining increasingly older DNA sequences and secondly, ensuring that the genome is of high quality. The oldest DNA sequence obtained to date is the 700,000 year old horse genome from Canada, a far cry from what was once an hypothesised maximum of 100,000 years old (Shapiro and Hofreiter, 2014). Sequencing technologies have also drastically increased genome coverage (how many times a gene is “read” a bit like each time you re-read a book you pick up on more information and with better accuracy). The Denisovan genome, for instance, before the use of the new sequencing technology enabled a coverage of 1.9 fold, which increased dramatically to 30 fold once the new techniques were applied. Nevertheless even with the new technology to analyse fragmented DNA, Shapiro and Hofreiter (2014, p. 1236573-2) state “it may not be possible to sequence any eukaryotic palaeogenome truly to completion”- a sad case indeed for the 11 year old boy who once asked me at a Science Brainwaves workshop “can we bring monsters back?” Assuming he meant dinosaurs and without getting into the logistics with him, I gave him the theoretical but not entirely true response of ‘yes’. He then exclaimed “COOL” really loudly and wondered off. To be honest, I didn’t really want to break his heart, and I may just have inspired him to become a scientist! A similar question was posed (in a considerably much more professional manner) at the Royal Society meeting in London Ancient DNA: the first three decades in November 2013. Towards the end of the talk The Future of aDNA by Professor Michael Hofreiter, a colleague from UCL asked “can we reconstitute from ancient DNA (putting aside the technical details) a viable sequence to create a viable organism?” The answer was a resounding no. When it came to resurrecting dinosaurs, Professor Hofreiter quite clearly stated that the field of ancient DNA will never be able to go that far back in time. With an added flourish came the phrase “don’t waste your time or money!”
So should we be worried about dinosaurs chasing us, or Neanderthals taking over? With the advancement of technology opening up the possibility of resurrection, it is only those that have not been extinct for very long that could be resurrected, such as the dodo or the passenger pigeon. The debate on this however continues: It is through this approach that together scientists, policy-makers and the public can work together to ensure that this new science is used in a mature and sensible way. As for my best friend, she is relieved and hasn’t had a dinosaur nightmare since.