The DNA Bank: The Frozen Ark

Jennifer O'Mahony

Could you tell me about the origins of the Frozen Ark project?

Mike Bruford

The actual origins of the Ark go back to 2004. It was the result of some research by my predecessor, Professor Brian Clarke, who was studying some endemic snail species in Tahiti in the South Pacific, where he saw the ill-advised introduction of a biological control snail predator that wiped out his study species. He realized, at that point, that if he didn’t do something, all of that genetic information, all the evolutionary research that he’d done, would be lost forever. So, he brought a lot of those animals back to the Zoological Society of London and Nottingham University. This really got him thinking that he needed to do something about rescuing genetic material from the species that were about to go extinct. That’s what motivated him to set up the Ark, which he did with his wife Anne Clarke.

Jennifer

The Ark is a useful metaphor for what you’re doing, but I’m guessing it deviates slightly from the two-by-two in a boat model. What does your Ark look like?

Mike

So, our Ark is really aiming to freeze genetic material, cells, cell cultures, tissue, DNA. Anything that basically harbors genetic material, either in viable cells, or as tissue samples, or DNA samples, so that that material isn’t lost and it’s maintained properly. That’s needed for a whole variety of different reasons but mainly because we need to understand the genetic diversity of species that are close to extinction if we’re going to manage them properly. Also so that we keep a record of the genomes of these organisms, if they do go extinct.

And so yes, we deviate from the two-by-two model very much, in the sense that maintaining the genetic diversity of two individuals is not enough for populations to remain viable in the future. So, we store lots of material from species, and we encourage organizations to collect and maintain collections of that nature, which properly represent the genetic diversity of the species they’re trying to save.

Jennifer

How many species have you collected material from since 2004? Hundreds? Thousands?

Mike

Thousands of species, and tens of thousands or even hundreds of thousands of actual samples. Species is one thing, but the number of samples is another. Although we have our freezers at Nottingham and at the Natural History Museum, the Frozen Ark is a federated partnership, so there are lots of freezers around the world that are collecting material that are members of the Frozen Ark, which is why I never really know exactly what we’ve got, because that’s an ongoing process. What we do is provide coordination, databasing, and advice to all of these nascent biobanks that are being set up, especially in developing countries.

Jennifer

What kind of DNA material is best?

Mike

The very best of all is cultured cells, so live cells. You can take cells from many tissues of the body, but people mostly take skin, and then you can grow them. For that, you need to culture the cells, which is technically tricky and there aren’t many places that do it—especially for lower vertebrate animals and invertebrates—and then you need to maintain those cell cultures at -200 degrees [Celsius] in liquid nitrogen, and then periodically draw them and regrow them. It’s technically demanding, but it is important. It can be frozen sperm. It can be frozen eggs. Next after [viable cells] is high-quality tissue, so tissue that’s been taken from live animals or animals that have just died. Muscle tissue, you know, that kind of stuff. If an animal, unfortunately, has to be euthanized or dies in captivity in a zoo, for example, or if it happens in the field, then freshly collected muscle tissue that we can then freeze down to -80 degrees [Celsius] is the next best thing, because that provides a large amount of DNA for future use as well. But we’re also very happy to collect other material, such as blood or DNA that’s already been extracted many moons ago. For some species, we’re even willing to accept non-invasively collected material like feces, hair, or urine, because they do contain small amounts of DNA, and that’s better than having nothing.

Jennifer

How do you decide which species to focus on, given the alarming decline in biodiversity worldwide?

Mike

That’s a question about prioritization, and that’s difficult because prioritization in conservation has always been a difficult topic. People don’t like to make life or death decisions. In our case, what we’re trying to do is maximize the evolutionary diversity of the material we get. If you’re working especially with captive populations and conservation, the temptation and the reality of the situation is that you’re often dealing with enigmatic large animals.

But what Brian Clarke really pointed out at the very beginning of the Frozen Ark is that if we do that, then we risk losing far more, because all of the most ancient lineages of genetic diversity that have evolved on this planet lead to invertebrates and lower vertebrates and microbes as well. We don’t want to lose that information, so we are very keen to make sure that we have an even representation of all of the diversity of life on the planet, not just the really enigmatic species. They’re the easiest ones to get material from, ironically, but it’s really important that we maximize, so what we aim to do is fill in as many gaps as we can across the tree of life and make sure that we have as many species represented.

Jennifer

I suppose when people think about the Ark, they think very long term, but is there any application for this material today?

Mike

We work on two timescales. The long-term timescale is storing genetic material for future generations, largely because we have no clue at the moment what could potentially be possible with that material. But we also are focused on using the Ark as an active repository. So, by storing material from populations now, we’re storing the information that allows those populations to be managed better before they become close to extinction.

For example, one part of CryoArks biobank has all the material that’s been collected from zoos and aquaria throughout the UK. If they want to manage their captive breeding programs, then they can take material out of the bank, DNA profile it, figure out who’s the most closely related, avoid mating those two individuals, and maintain diversity by using the genetic data that we’re able to get from the frozen collection. You can take the diversity that you have and use that to reinvigorate populations in the present day.

Jennifer

Do you feel as though you’re rushing to collect genetic material in the nick of time or is it quite a slow process?

Mike

I mean, both really. If I think about my own research, I’m a geneticist working on endangered species, and there are some species whose DNA I’ve had my hands on over the years that have gone extinct. For example, we work on black rhinos, and we have DNA samples from what’s known as the western black rhinoceros, which existed in Cameroon and Nigeria until the mid-2000s. So, we have DNA from individuals in those populations, which were declared extinct in 2010. And there are a number of examples of that—where we’re holding DNA material from populations that are now extinct. And it’s a sad fact that if you want to get genetic material from any of the populations that exist, or that are relevant for conservation of species, the best place to find it nowadays is in museums, because many of those populations are either so small you can’t access them (for sensible conservation reasons) or because they’re actually extinct.

Jennifer

I think a lot of people read reports about the decline of biodiversity with a lot of horror, and they feel quite helpless in the face of the statistics that we see. What would you say are practical things that the average person can do to support initiatives like yours or to ensure biodiversity where they live?

Mike

Get involved. All organizations like ours critically depend on the public for funds, whether it be by donations or by fundraising for them, for advocacy in persuading their friends and colleagues that this is important or by re-engaging with nature. I think that’s been the biggest problem—that people are so busy staring down at a screen these days that they’re not looking up and engaging with nature. We need people who are advocating for us, who are acting as citizen scientists—in our case, collecting material even. The charity sector and conservation is run on grace and favor largely. We really struggle for funding, and people need to understand that it’s not just giving large chunks of money that is a way that they can help but by actively engaging with us and talking to us.