Resurrecting the Past

Recently there has been a little bit of media attention focused on this rather innocuous looking frog from Queensland, Australia:

LBJ (Little Brown Job) frog. Photo by Owen Kelly

Meet Rheobatrachus silus, or better known as the gastric-brooding frog (well ok, better known to us zoologists). This might leave you wondering what all the fuss is about, but its one special little fellow. The more intuitive ones of you may have read its name and asked “Gastric-brooding? Really? Really?”. And basically the answer is simply, well, yes. This little frog got its name from the fact that it swallowed its eggs, incubated them in its stomach until they hatched, then ‘gave birth’ to the perfectly formed little froglets out of its mouth, like this:

R. silus 'giving birth' from its mouth. Photo the Australian Government Department of the Environment, Water, Heritage and the Arts

Not quite so innocuous now, huh? You may or may not have realised my use of the past tense there. It used to swallow its eggs and incubate them in its mouth, because they don’t do this anymore. The species became extinct in the mid-1980s. No one knows for sure, and in truth it was most probably a mixture of things, but its commonly thought that this was due to both habitat destruction (isn’t it always?), and the continual spread of an incredibly virulent, amphibian specific fungus called  B. dendrobatidis which causes the deadly disease Chyridiomycosis.

So I suppose you’re still wondering what all the fuss about this amphibian was for? Well, thats because the ‘Lazarus Project’ (the name for those who wondered, is taken from a story in the Gospel of John, where Jesus raises Lazarus from the dead), have claimed to have successfully taken the DNA from a preserved specimen of R. Silus collected in the 70s and placed it in a surrogate egg (from a closely related living species of frog) to produce an embryo. Now unfortunately these embryos only survived for a few days, but what it shows is highly significant. It shows the possibility that the resurrection or the ‘de-extinction’ using the cells from preserved specimens could, one day, be achieved.

To the best of my knowledge, this is the first time this has been achieved for a recognised species (in fact more impressively, R. Silus is even in its own genus) in its own right. In 2009 scientists in Spain did successfully manage to clone, implant and bring to term a Pyrenean Ibex (Capra pyrenaica pyrenaica), a subspecies of the extant Spanish Ibex (Capra pyrenaica), which went extinct in 2000 (the foal survived for 7 hours, before it died of complications). But as stated this was just a subspecies, and not a species in its own right.    

The Pyrenean Ibex. Photo from blogueiros.axena.org 

So what does this mean? It gives weight to a growing field within conservation biology of cloning extinct species. There are many projects worldwide trying to resurrect long dead species, from mammoths (Mammuthus sp.), to aurochs (Bos primigenius) to passenger pigeons (Ectopistes migratorius), and this news to them is a huge leap forward. This experiment went to show that the limitations for cloning long  dead species is technological, not biological. But that’s not to say it will be the same situation in 10, hell even in 5 years time. And so we need to be addressing the wider issue here of not can we, but should we? 

So, what’s the point then? Why bother spending all this time, money and effort to bring back an extinct species? Well a lot of these arguments are actually very similar to those used to argue for protecting endangered, still living species. There’s the ‘ethical’ reason, that (some of) these species were driven to extinction as a direct result of the activities of man, and so what gives us the right to let some go extinct, whilst others survive? This would give us a chance to readdress this balance.

But there are people who have suggested, and indeed there are projects focussing on, bringing back species such as the Mammoth, or the Sabre-toothed cats (Smilodon sp.). Its far from certain that these animals were driven to extinction by mankind, in fact it’s quite possible that a warming climate was to blame, thus making their extinction at least partially natural. If an extinction event was natural, should we rectify that? 

This is where the ‘ecosystem function’ argument chimes in. This states that there are many species which fulfilled vital roles within a certain ecosystem which have subsequently gone extinct. One of the main examples cited for this is that of the Mammoth. It is thought that their presence helped to maintain the Russian steppe ecosystem as they pulled down trees and opened up grasslands, much as modern savannah elephants (Loxodonta africana) do today. So even if a species was driven to extinction by natural causes, there is still an argument to bring it back in order to restore an ecosystem.

The frozen carcass of a baby mammoth, and possible source of mammoth DNA. Photo from blogs.discovermagazine.com

However, there are evidently some major issues with projects such as these. The more obvious is that of cost. These projects cost money, and lots of it. Would the time, money and resources not be better spent to preserve what still survives today, rather than hankering after something from the past? Rather than recreating R. silus, should they not first try and identify what it was that drove them to extinction in the first place, and try to stem this? I mean this surely has to have priority, as even if they were successful at breeding these frogs, they have to be released somewhere after all. One of the lead scientist of the Lazarus Project, Professor Mike Archer, has already met controversy for his part in the project to clone the Thylacine (Thylacinus cynocephalus), or Tasmanian tiger. Some claim that he diverted resources away from some more promising projects to fund one trying to extract Thylacine DNA, a project which was stopped after only 3 years.

And finally, we come to another fascinating thought. Will a clone of an extinct species still be the same species, or will it in actual fact be something different? This may sound like mindless nattering, but it raises an interesting point: Is the definition of a species what is contained in its DNA, or does it also include other external factors, such as learnt behaviour? Modern day elephants learn from older members of their group, and so I don’t think it’s too presumptuous to imagine it was the same for mammoths. If they are ever cloned, will the mammoth calves ever become true ‘mammoths’ if they weren't able to learn their behaviour from 

another one?

The cloning of extinct species will happen, there’s no doubt. As technology advances, and techniques become more refined they will be utilised by conservationist. This isn’t necessarily a bad thing, it can and no doubt will be used as a last ditch fail safe for many species. I just hope that it doesn’t allow people to become complacent with the degradation of the environment if extinct species could be cloned again some point further down the line.

Over and Out.

[Edit: Ibex foal survived for just 7 hours, not the 7 days originally stated]