MR. PAUL BROWNFrom WAMU 88.5 at American University in Washington, welcome to "The Kojo Nnamdi Show," connecting your community with the world. I'm NPR's Paul Brown, sitting in for Kojo.

MR. PAUL BROWNIn the movie "Jurassic Park," cloning brings dinosaurs back to life. Don't worry, it's still impossible. But scientists may soon be able to bring back more recently extinct animals by recreating their genome. What if the mammoth could roam the arctic tundra again? Or the now-extinct passenger pigeon could return to the skies of North America. Researchers hope to use molecular biology and genetic engineering to implant DNA from extinct animals into their living cousins and recreate bygone creatures.

MR. PAUL BROWNA group of scientists, writers and environmentalists has coalesced around the idea of de-extinction and is gaining momentum for the work. Replication of extinct animals won't happen tomorrow, but the possibility of eventual success is raising serious questions about the wisdom and the ethics of reversing history. Joining me to talk about bringing extinct animals back to life is Jamie Shreeve. He's the executive editor for science at National Geographic magazine. He joins us in our studio. Jamie, thanks for coming in.

MR. JAMES SHREEVEGlad to be here.

BROWNBeth Shapiro is professor of ecology and evolutionary biology at the University of California at Sta. Cruz, joining us by phone. Beth, thank you for being with us.

MS. BETH SHAPIROThank you.

BROWNAnd Ryan Phelan is co-founder and executive director of Revive and Restore. Joining us also by phone from Sausalito, CA. Thank you very much, Ryan, for coming in and being with us.

MS. RYAN PHELANThank you. Delighted to be here.

BROWNAnd if you're listening now, how do you feel about bringing animals back from extinction? Who should decide whether to recreate a long-gone animal and why? You can join us on the phone. Our number, 1-800-433-8850. Write us at email, or email at kojo@wamu.org. Or you can check us out through our Facebook page or send tweets to @kojoshow. We'd love to hear from you as we get our conversation started.

BROWNRyan Phelan, to start out with you, you and your husband Stewart Brand who was the founder of the Whole Earth Catalog in the late '60s started a group called Revive and Restore to address the complex issues surrounding de-extinction. How did you become interested in this field and what is your group's mission?

PHELANWell, Paul, our mission really is very clear, which is to help spearhead, I think, a growing movement here to use genomic technologies to both protect endangered species and to potentially bring back species from extinction.

BROWNAnd why do you believe that that is something that should be done?

PHELANWell, I think what we'd seen and both Stewart and I have for different reasons been involved around genomics just really almost, in some ways, as a sideline to some of our current businesses. And I think what we saw with the power of these technologies and the exponential shrinking in the cost of these technologies and what we couldn't help thinking is, is there a way that we could better use these technologies to help with conservation?

PHELANCould we use these technologies to help basically create richer ecological environments. And one thing led to another, Paul. And the bottom line is we started getting together a number of different scientists from around the world and kind of asking this question, is the time right to be doing this? And we started getting some very interesting uptake.

BROWNI guess one of my questions here initially is, is there ever a right time to be doing this? Or is the story something that should just be playing out as it has played out? How do you feel about that?

PHELANWell, I think the first thing I'd ask is how is that story played out? I mean, so far what we've seen the major causes of really all the extinctions in the last thousand years have been caused by men, either through the loss of habitat or through hunting pressures or a variety of different reasons that we have caused these extinctions. So the question is, now that technology is starting to become available to reverse that trend, could we or should we actually interfere?

BROWNAnd you feel, obviously, that it might be a good thing to interfere, as you put it.

PHELANWell, we do think it's the right time to raise the questions. And I love it that your show is really trying to help, you know, encourage this discussion and this debate. And that's really why we, you know, are really trying to help surface this because we do believe that these technologies could be used and that they are being used in different ways already. The San Francisco Zoo has created something called the frozen zoo, which has been running for 35 years, actually storing DNA and now increasingly cell tissue from endangered or extinct species.

PHELANNow the question is, they've got this frozen zoo bank, can they continue now to start to actually use those tissues to bring back species?

BROWNAnd I hope we can find out a little more about that as our conversation continues. And with that in mind, let's go to Jamie Shreeve of National Geographic whose de-extinction story is the cover story on next month's issue. And, Jamie, how did you become interested in this research field and helped to convene what was the first meeting of scientists working on de-extinction projects?

SHREEVEWell, first, Paul, let me correct that. I didn't write the story. I edited the story. Carl Zimmer, one of our best science writers wrote the story. But I got into it initially over lunch with Stewart Brand. He brought up, among many other interesting topics, his interest in this bringing back the passenger pigeon. And it seemed like a no-brainer for National Geographic to get involved.

SHREEVEWe have a long history of conservation efforts and a long history of funding leading edge science. So it seemed like this is a perfect combination of conservation and science. And as long as the geographic society itself stays, you know, in a position of helping to promote dialog on this, we're not pro or con. But I think it's a fascinating topic that everybody should be knowing about now.

BROWNMm-hmm. Briefly, for people who haven't perhaps given this much thought, there are probably a lot of us who haven't, what are you finding out? What are the big threads of thoughts surrounding the idea of de-extinction, the pros, the cons, the risks, the desirables, the possible desirables?

SHREEVEWell, let's start with the possible desirables. There are a lot of animals, as Ryan pointed out, that have gone extinct very recently because of human action or, in some ways really, human inaction, sort of a thoughtless approach to the environment, to nature. And to bring these back, I don't think we necessarily have some moral obligation to do so, though some people did take that line.

SHREEVEBut I think we do have a great benefit to be, one, by increasing the biodiversity. A lot of these species were unique. Well, all species are unique. But some of them had particular kinds of biology that we don't know about now because they're gone. And if we can bring them back, we can study them better. For instance, a mammoth. We know what an elephant's biology is like and we know what mammoth's bones are like.

SHREEVEWe know what their, you know, their skeletal structure. But how much more can we learn from a mammoth if we could actually confront one, say hello to one.

BROWNAnd we wouldn't know until we could.

SHREEVECorrect.

BROWNRight.

SHREEVESo that's one huge benefit. On the other side of the ledger, I think there is a lot of concern that if we were able to get to the point where we could readily bring back extinct species, it would reduce the pressure and the urgency of keeping the ones that are endangered now. And that would be a bad thing. I mean, I think we need to consider this as two different questions and not think of this as a solution to dealing with endangered species because it's not.

BROWNDo you worry about unexpected outcomes that could be negative given the fact that ecologies have changed, the climate has changed, the total environment for some species might have changed to the point that either a species if recreated couldn't survive or it might pose a new danger to species that are presently on the earth that weren't there back in the day.

SHREEVEBoth things are possible. Both things, though, also have possible pluses too. If you think about species that has gone extinct and its environment is no longer there because it's become polluted by human activity, well, bringing back that species might actually drive a conservation effort to bring back the ecosystem as well and, you know, correct the pollution on a larger scale. So, in that sense, it could be a sort of foot in the door towards something very positive.

BROWNI want to get to that in a little bit. Let's go to Beth Shapiro. Beth, you're an evolutionary biologist and an expert in what's called ancient DNA. Explain how you used genomics to study ancient mammals, ancient animals and their habitats, if you could, for us.

SHAPIROSure. Well, we know that in the best of scenarios, so generally this is -- we're in a very cold place, where it's dry -- that the DNA within the cells of an animal that's died in their bones or in their hair, in their tissue and teeth can survive for quite a long time. In some cases, up to several hundred thousand years. And ancient DNA, as a field, has been interested in using these DNA sequences that we can recover from extinct animals to try to infer how populations changed in the past.

SHAPIROWe've been asking, for example, questions about how populations of animals that are either extinct or survived to the present were affected by past periods of climate change. So as we went into and then came out of the last ice age, why did some species survived and others didn't? We can use the genetic information from these fossils to look at the amount of diversity in populations through time and understand or try to infer how these populations responded in the past.

BROWNAnd this could help us perhaps understand how we might survive in this period of what appears to be climate change?

SHAPIROSure. Humans, I think, we're not going to have any problems surviving. But it's other things we should worry about more. But presumably if we can understand what distinguishes some populations or species as being more adaptable in the face of climate change, we can use that information to make more, say, science-based decisions about conservation and management of the populations today.

BROWNCould we look for a moment, all three of us, at the different methods that scientists are using to try to bring back extinct animals. What are some of the methods that are being used? And why don't I start with Ryan Phelan and then move around a circle. Ryan, what are some of the methods?

PHELANSure. I think there are really basically three methods that are pretty well know right now that are being used. The first one is referred to as back breeding. And this is basically a technique that have been going on ever since we've been breeding animals or plants for that matter. And the best example is a group in the Netherlands that are trying to bring back an ancient form of cattle called the uruk.

PHELANAnd they're having a lot of success, moving it along basically turning the cattle so that they are basically reflecting more and more of the phenotypic trait, as they say, the expression of the genes to bring back the ancient cattle look and feel and actual function of that particular ancient species. The second technique being used is referred to as cloning. And I think we probably all have heard that terminology from the early days of Dolly and basically replicating cell tissue from and, in the cases where they've done the cloning has been primarily been where they're using the exact same species and replicating it.

PHELANBut there is one great example just over 10 years ago now in Spain where they actually brought back the very first extinct species called the Pyrenean ibex.

BROWNIs this the bucardo?

PHELANYeah, exactly. And...

BROWNAnd this is an animal which, by the way, is the -- starts out the National Geographic article coming out next month. It tells us about that story, the resurrection of the bucardo.

PHELANRight. And it's a beautiful story of these scientists working so hard having seen the last of this particular type of species there and realizing that it was the last. They had collected cell tissue from that animal and several years later they found the animal had died in the forest. And they went back into that frozen specimen and they basically reengineered that tissue, brought it back to life again by using another closely related species. And that goat actually gave birth to the first de-extincted species, the original Pyrenean ibex. And...

BROWNSo cloning is the second method.

PHELANYes. And the third method, which is -- has not yet come to fruition but is certainly one that many different people have a lot of interest in, and that we would be calling genetic engineering. Basically where instead of reading the DNA now we're starting to consider writing the DNA. So they call it unreal replacement. And basically you would take the most closely related relative to an extinct species.

PHELANUnderstanding both of those genomes and comparing them you would actually start to alter and switch gene by gene to get the traits that you want to bring out from the...

BROWNAnd these would be traits that you would recognize in the extinct animal...

PHELANExactly. So...

BROWN...that you want to bring out. So it would be a close relative perhaps or similar in numerous ways to the original but not the original.

PHELANWell, and that's a very interesting fine line that you bring up. At some point it goes from being truly a proxy of the extinct species. And at some point you may say it's the real thing because at the end of the day this is what goes on with evolution all the time. We -- you know, there is a real question about what is really pure with any of us as species. I mean, after all, we actually have some Neanderthal genes.

BROWNJamie Shreeve may have a brief comment here on this.

SHREEVEWell, I just wanted to add to the cloning discussion. All these techniques, it's this cutting edge work that's making this possible. And one thing that they're doing now with cloning is that they can take what's called pluripotent stem cells from the target extinct species and turn them into germ cells, which are the precursors of sperm and eggs. Implant those into the embryo of an extinct living relative. And then when that embryo grows up and is born it's just a normal extinct -- you know, let's say a chicken -- but it's carrying passenger pigeon sperm and eggs.

SHREEVESo when those -- when it gives birth and those babies grow up they will -- I mean, they'll be giving birth to a different species, which is pretty cool.

SHAPIROCan I add something to this actually?

BROWNIs this Beth?

SHAPIROYes.

BROWNAnd I was just coming around to you next to get your input. So perfect timing.

SHAPIROI just wanted to say that when we think about bringing an extinct species back to life, cloning is normally the first thing that comes to everybody mind. But from the perspective of someone who works with ancient DNA, it's important to point out that as soon as an animal dies that DNA inside everyone of its cells starts to breakdown. And it gets chemical modifications from ultraviolet radiation, from water, from oxygen, from bacteria that are in the soil, etcetera. And it just breaks down.

SHAPIROAnd eventually over time there's nothing that's usable left. And so when we think about bringing an extinct animal back to life we would have to find a completely intact cell and we're not going to. That just doesn't exist for something that's extinct, even in the coldest most frozen environments. We're not going to find a cell like that, which is why we have to turn to this third method, the genetic engineering method.

BROWNSo really what you're saying is we can't bring back a species exactly. It's not possible. The DNA doesn't exist. We can get very close possibly.

SHAPIROWe can get very close possibly but there are other problems with this approach that we haven't even thought about. I mean, there are processes going on that are epigenetic, that are outside of the genome itself where even if we could know the whole sequence of the genome, we don't know about what's going on outside of the genome. We don't know about how much, for example, the micro biome that lives inside the gut of an extinct animal actually has to do with making it look and act the way it does. And these are things that are outside of the genome but also not really accessible to us yet.

BROWNWell, we want to continue this discussion in just a moment. Stay with us on "The Kojo Nnamdi Show where we're talking about de-extinction. And we'll be welcoming your calls at 1-800-433--8850 when we come back. This is 88.5 WAMU.

BROWNWe're back with "The Kojo Nnamdi Show." I'm Paul Brown from NPR News sitting in today for Kojo talking about the idea of de-extinction, bringing back species that have gone extinct with Jamey Shreeve, executive editor for science at National Geographic magazine here in the studio with us. Beth Shapiro, professor of ecology and evolutionary biology at the University of California at Santa Cruz. And Ryan Phelan, the co-founder and executive director of Revive and Restore. She's also joining use from Sausalito, Calif.

BROWNAnd let's go to the phones, bring some listeners in now to join us. John from Olney, Md., you are on the air. And what's on your mind, John?

JOHNYes. You mentioned that the Neanderthal is a cousin of us and we understand we share some of its genes. Why not bring it back, not because it's a Neanderthal but it's on the way to the big brain, which we know that we have that they missed. I'm a physicist.

BROWNOkay, Ryan -- I mean, Jamey Shreeve may have a comment here. Jamey?

SHREEVEWell, I love Neanderthals. I've written a lot about them and I would theoretically or abstractly love to see a Neanderthal. But I think the problem there is an ethical one. Neanderthals are human beings -- or were human beings. And we would be bringing back a human being into a human environment and culture, which it has no relationship to. And then how are you going to deal with its -- that relationship? Is it something to study or is it something to send to school and educate along with your other children? It's just too complicated and ethically too complex.

BROWNYou know, earlier when I was talking with Ryan Phelan, I said, you know, is this necessarily a good idea to bring species back. We have an email here, Ryan, from an environmentalist who says, "Please do not say that the environmental community has coalesced around this is a good thing. We have not. There are ethical and practical issues surrounding this and scientists are not going to know those. Why spend money on real conservation when all we have to do is freeze some species?

BROWNCongress will have a great incentive to defund current conservation programs if all they think they have to do is freeze tissue. There would also be no point in bringing back species if their habitat is trashed." So, Ryan, let me get you in on this conversation. How do you react to that email?

PHELANWell, first of all, I would never say that the environmental movement has coalesced on anything yet because, you know, these are ideas that are just being put out there.

BROWNRight, right.

PHELANAnd -- but that being said, we have seen a lot of people from the conservation field coming forward saying, the conservation -- conservation as a field really coalesced itself around a real crisis of conservation. And as a sort of -- it was developed as a crisis discipline, I've heard people say. And this is the first time, when they start to think about the extinction, that they can actually bring hope to this field. So I think that there is something going on here that all environmentalists ought to pay attention to.

PHELANBut going back to this whole question of should it be either/or, should we only be spending money on preserving habitat or should we in addition look at being able to develop new technologies that might be very relevant to protecting endangered species. And I think -- you know, really I want to encourage people to think about this as being both. You know, you don't want people to ever take their eye off the ball of preserving and protecting. But if we can make it an additive situation I think it's more of a win-win.

BROWNBeth or Jamey, does either one of you have anything to contribute to that -- to add to that?

SHAPIROI would like to say, it's also critical to realize that a lot of the technologies that we're talking about using here, we're not going to be developing explicitly for bringing extinct species back to life. These are molecular biology techniques and genetic engineering techniques that have enormous and important roles to play in questions about human health and questions about evolution more broadly that we can apply to this -- the extinction effort if we want to. That we're not going to be asking for money to be taken away from other programs, and particularly not from conservation programs.

BROWNOkay. And it sounds as though what you're saying is that the point of this endeavor, of the inquiry is not necessarily to bring species back. The point is to learn and to gather understanding.

PHELANNo, Paul, I have...

BROWNIs that fair or is that not...well, let me get Beth to answer this first and then come back to Ryan.

SHAPIRORight. I would say that there's two things there. The point of this conversation is to really consider what it would be to bring an extinct species back to life and to think hard and learn about scientifically how we would go about doing this. And I think that it is an interesting outcome that could come from this work. All I'm saying is that the money that's coming for it is not going to be taken away from other equally good scientific ventures.

BROWNRyan, where are you on this?

PHELANI completely agree with Beth. And, you know, I encourage people to think about it as a way of actually potentially even infusing new biotech money that could be going into this field of molecular biology and become a win-win for the environmental field as well.

BROWNLet's go to Bruce in Mount Rainier, Md. Bruce, you're on the air.

BRUCEHi. Bruce -- Paul, you know me through the old time music world, but I don't have any questions about reviving extinct banjos.

BROWNGood.

BRUCEI have some more pertinent questions for your guests.

BROWNThat makes us all heave a great sigh of relief here. Thank you, Bruce. Bruce Hutton (sp?) .

BRUCESome years ago I heard about experiments where they were using the dormant change in chicken s to bring back more of their ancestor's characteristics, like a chicken with teeth. And I wondered if that was just a proposed experimental program or if there's been any success in that area.

BROWNAnyone have an answer for that? Thanks for your call, Bruce.

SHREEVEThat's -- Bruce is referring to an experiment that's popularly known as the chickenosaurus that Jack Horner and his colleagues are talking about. I really don't know how far along they've gotten but what they're trying to do is basically reverse engineer a living dinosaur, a chicken, to have traits that have long ago gone extinct by manipulating the regulation of their genes. I think it's an interesting line of work but it's not going to create a dinosaur. It's going to create a chicken with teeth and a long tail.

BRUCERight.

BROWNDoes that help answer your question, Bruce?

BRUCEIt does and I think you've already answered the next question I wanted to propose. And that was if they do bring back many of the characteristics of an extinct animal, I've heard some say that it won't be the extinct animal but more of a hybrid with characteristics that look like the extinct animal.

SHREEVEWell, that's a frequently posed question. And I think there's some differences among maybe some of us even on the line today about that. It really is -- you know, there's one point of view that if it, you know, quakes like a passenger pigeon and walks like a passenger pigeon, it's a passenger pigeon.

BRUCEI think I've heard that, yes.

SHREEVEYeah. there's another point of view that really, you can never bring back the extinct species because that species exist in time and space like individual do. And they are born and they live and then they die. And you cannot resurrect something that is dead. You're bringing back something that approximates that species. And I think there has to -- you have to acknowledge -- I think even Ryan would have to acknowledge there's some truth in that. But you can get closer and closer to the extinct species to where maybe that question is not that important.

PHELANAnd I think something to add...

BRUCEYeah, I'm glad you don't want to consider realistically bringing back the Neanderthal because that would be even sadder than Rip Van Winkle.

BROWNThank you very much for your call, Bruce.

BRUCEAll right.

BROWNAppreciate it. Let's go to Kevin in Arlington, Va. Kevin, you're on the air.

KEVINYeah, hi. I had two overarching points. And I'd just like to start out and say that time after time mankind has tried to change the natural system to suit our needs. And every time it's ended in more environmental harm than good. I suggest that we try to alter our behavior to fit the current natural system. So firstly, we'd be far better suited to focus our time and treasure on halting future extinctions in environmental preservation as it is. And I know this has been discussed, but it really is a dangerous game to produce the excuse of, oops, there goes another species, but it's okay. We'll just bring it back if we want.

KEVINThe concept of bringing back an extinct animal to somehow inspire humanity to recreate a habitat is -- seems to me a fool's errand. It's hard enough to preserve a habitat to protect a species on the verge of extinction as it is. And then secondly, my question is, who would own these animals? Assuming we retain copyright law in genetic engineering process to encourage innovation and financial investment in the process to profit licenses, biotech companies that conduct these de-extinction experiments would own these animals and their offspring, assuming the Supreme Court rules to the plaintiff in Monsanto v. Bowman.

KEVINSo if and when these animals breed with animals in the wild, as genetics will likely be barred from existing species as a genomic template per say, would these institutions own wildlife? The academic and the scientist in me finds this issue fascinating but the environmentalist, concerned citizen and ethicist in me says stop.

BROWNUm-hum. A reaction from our guests? Thank you, Kevin.

SHREEVEWow, I have to agree with a lot of what the caller just said, that...

BROWNJamey Shreeve here. Yeah.

SHREEVEThe -- I don't agree however, that all of our efforts have been negative and unsuccessful when we try to remediate environments that we have destroyed. If we -- sometimes we can -- we've had invasive species that we've introduced and then we're able to introduce another species that takes care of that problem if it's handled correctly and carefully. And I think this is what we're trying to do here and now as well with this issue. We're trying to do it carefully and correctly.

SHREEVEBecause as the science goes forward it will be done, and the issues that you brought up about patenting and ownership will come up. But let's set the table correctly and go forward from there.

SHAPIROI think that's the important thing about the discussion that we're having right now. I mean, we should keep in mind…

BROWNAnd is this Ryan?

SHAPIRONo, this is Beth.

BROWNThis is Beth, yeah.

SHAPIROWe should keep in mind that this isn't something that we can do today. And what we're doing, what Revive and Restore -- if I might speak for Ryan here -- is trying to do is bring people together, scientists and ethicists and conservationists and environmentalists to have a conversation about what the questions are. What are the outstanding problems and what do we need to do to come up with a way to do this that's going to make the most sense from an environmental and a scientific perspective?

BROWNRyan, do you have a comment here?

PHELANI do. I think that, you know, I completely agree with all the people that have just spoken forward about the need to look into all of these issues. But I'd also like to encourage us, and we have been doing this, of trying to speak with the experts who have been reintroducing species already. Now these are not completely, you know, reengineered species, but in some ways they are.

PHELANAnd they're -- you know, a couple of really good examples, one is the peregrine falcon that, for any of us bird lovers, you know, we just relish seeing a falcon streak through the sky. Well, that peregrine falcon was virtually extinct on the east coast. And a number of different birding organizations got together and scientists, and they actually did a series of releases of different hybrid birds to actually figure out which species, which as a subspecies would be able to flourish.

PHELANAnd the peregrine that we have today is one that is exactly the result of all of those experiments. And it's a complete mongrel of a bird, if I may say so. And none of us are worried that it's not pure. And none of us thought about that we shouldn't actually try to protect that species. And I can go through the list. You know, the California Condor's another one, that if we didn't utilize the Andean candor to help in a release program, we wouldn't see condors today. So I...

BROWNWell, do you still understand some of Kevin's reservations who called in a moment ago?

PHELANWell, I think...

BROWNEverything from ownership to the difficulty of even maintaining an environment for the creatures that we already have. And then this becomes yet an added set of complexities when one reintroduced a species through either cloning or some other method of basically bringing an extinct species back.

PHELANWell, I think I'd separate the issue and the challenge of the work that it takes to reintroduce an animal into the wild, like the condor, the falcon or the wolf in Yellowstone. It is complex. It's costly, and de-extinction will never be as easy to do as even rewilding program. So no one is suggesting that it should be done in lieu of, but I do think that the question that he has raised around where will biotech go down the road and where will potential for patent issues come up. Those are, you know, that is clearly new terrain, but certainly in the work that's been to date where we're taking hybrid species and reintroducing them into new terrains, the issue of patent has never come up.

BROWNLet's take a brief break. We'll be right back and continue our conversation on de-extinction with Jamie Shreeve, Beth Shapiro, Ryan Phelan, and you on "The Kojo Nnamdi Show." I'm Paul Brown sitting in for Kojo today. This is 88.5 WAMU.

BROWNWelcome back to "The Kojo Nnamdi Show." I'm Paul Brown from NPR News sitting in today for Kojo. Our topic, de-extinction. Jamie Shreeve is executive editor for science at National Geographic Magazine. Beth Shapiro is a professor of ecology and evolutionary biology at the University of California Santa Cruz. Ryan Phelan is co-founder and executive director of Revive & Restore, and all of them joining us today for our conversation.

BROWNYour calls welcome at 800-433-8850. That's 800-433-8850. You can email us at kojo@wamu.org, or check us out through Facebook. Send tweets to us @kojoshow. We're always happy to hear from you. And let's go to the phones now to Mary in Norfolk, Va. Mary, you're on the air.

MARYHello.

BROWNHi.

MARYHi. The question I have has to do with behavior.

BROWNMm-hmm.

MARYIf you were to bring back something like a passenger pigeon that has not parents, and birds often imprint, how would they learn basic behaviors like building nests, what materials to use and where to go and what to eat?

BROWNJamie -- or no, who can talk with us about that?

SHREEVEI think Ryan is probably best.

BROWNRyan, are you a good bet for this?

PHELANI'd be happy to chime in here.

BROWNOkay.

PHELANI'm not a scientist per se, but I'm a great advocate for bringing back the passenger pigeon, and I'll explain to you why. Not only a little bit about this bird's behavior I think is really interesting. These were the most common birds in North America a hundred years ago, and the way that the parents actually bred was they would do it in large sequential breeding. They would actually synchronize their breeding, and all the nest building was done at once by the parents. All the eggs incubated at the same time.

PHELANThe fledglings all grew up at the same moment, literally, and within two weeks all those parents left the birds. So of all the species, the passenger pigeon was not a -- they were not parents that would hang around and do that kind of training. They're very, very, hard wired genetically.

BROWNSo are you saying that your concern about bringing about a bird for example is minimized by the likelihood that the imprinting would be deep enough that the bird would be okay?

PHELANWell, exactly. In this particular species, there's reasons to believe that its behavior was more hard wired than any other species.

BROWNMm-hmm.

PHELANNow that being said, I don't want to dismiss the caller's concern about behavior. And one of the ways that we're talking about raising a new passenger pigeon is by using its most closely related species which is called the band-tailed pigeon, very common on our west coast, not on your east coast, and basically having the band-tailed pigeon imprint and do a lot of the training with the reared passenger pigeon chicks.

BROWNNow, assuming that a creature is pretty well hard wired, there are still, one would imagine, things that it would have to learn, and in an email from Jonathan here, we have the message, "Extinction doesn't just kill off a species, it ends all the species learned knowledge as does a species burrow, how a species burrows or migrates. So once the species is extinct, all the things the species does have to do that are taught are absent. How do you confront that issue?" Any of the three of you want to answer this? Jamie, do you have a comment?

SHREEVEI would just say that's a really good question, and not an easy one to solve. But again, we have to be -- understand that we're thinking of this in a really long time frame where we're going -- where the science is going to advancing, and where there may be ways of penetrating closer to where we want to go with this. True, I mean, if there are migratory patterns that are hard wired in say a, you know, a leatherback turtle extinct relative or something, I don't how you'd ever retrieve them, and that may be one deciding thing to -- whether you decide whether this is actually an extinct -- the extinct species or something that's still useful, but not quite the same thing.

SHAPIROThis is Beth. Can I add something quite -- just really quickly? I think this is a great question. It's a very hard question, and it's something that we don't really understand. We don't know how much of behaviors are learned or taught, versus how much of these behaviors are genetically encoded, and wouldn't it be nice to be able to learn that.

BROWNSo this might be one way to start to learn those things. Mary, thanks for your call. You kicked off a great segment in the conversation. I want to go to Tina in -- who has a question about this same issue, basically. Tina, you're on the air.

TINAOh, yes. Hello?

BROWNHello.

TINACan you hear me?

BROWNGo ahead. We can hear you. You're on the air.

TINAOh, okay. Well, yes. I guess my question was similar to the last one. I just wanted to know what the significance of this effort would be. Like what would it matter to bring back these species?

BROWNWho can answer that?

TINAThe significance -- what significance would it have to us.

BROWNYeah. Who can help us with that amongst our guests here?

SHREEVEWell, I'll take a first stab it, although I might have other responses too. One thing is that every species, like I said earlier, is unique, and many of these have biologies that we don't know about any more. There's a wonderful frog in -- or was a wonderful frog in Australia called the gastric brooding frog that gave birth by a female basically eating her own eggs and then growing the eggs up into froglets in her own stomach. She basically turns her stomach into a womb, and when they're ready to be born, she vomits them up.

SHREEVEIt's a bizarre and interesting behavior. One of the great brushstrokes on the canvas of life, you know, that we don't have any more. And if we had that species back, we could learn a lot about reproductive physiology that we don't know. So that's one answer anyway.

BROWNMm-hmm. Anyone else?

SHAPIROAnd I think I would just add to it, the answer is really the same as why do we protect endangered species? It's really no different than why would we consider bringing something back from extinction? We all believe that biodiversity is a good thing, and that the richer our environment and our species mix is, is a good thing. And really, what we're trying to do is just increase that biodiversity.

BROWNRyan, you know, one of the things that I read about the passenger pigeon in preparing for this program is that it was a very sociable and gregarious bird. That it, in fact, could not survive without huge numbers, and this is something that Jamie and I were talking just before we went on the air as well, and that at one point after the species had started to really collapse in the late 19th century due to overhunting and habitat destruction, there was an attempt made to keep the species alive somehow, and to keep it viable, and it simple couldn't succeed because there weren't enough birds, and these birds, as we've heard, migrate in huge numbers.

BROWNThey have this complex reproduction process that involves a tremendous community. Would this not be just about an impossible undertaking to bring back the passenger pigeon?

PHELANWell, we don't think it's impossible. We do think it has challenges, Paul, and I think you've raised some really important ones. The truth is, the science literature a hundred years ago on captive breeding was really sketchy, and it's quite confusing whether or not we can believe that these birds could not be kept in captivity or not. The size of those flocks, you know, will present some challenges, but we believe that there are ways that, you know, could be developed using homing pigeons and other things like that to help bring up the flocks.

PHELANBut I think more importantly you've raised a really important question which is how do you decide if you were going to bring something back which species would by the right candidate, and I think it's fair to say we're really in the very early stages of raising all these issues. Do you bring back something because it's a keystone species, do you bring it back because it's easy to bring it back, do you bring it back because it has habitat, you know. What are the criteria?

BROWNYou know, I've got a message from Keith in Silver Spring who says, "Bring these animals back to what? The environment is very different, and not friendly to these creatures. He writes just because we can do something doesn't mean we should. I say no to this. It's not fair to the animals." Okay. Let's get some input from our guests on that. Jamie?

SHREEVEWell, I don't think that it's always true that the environment is no longer there for these species. For instance the Pyrenean Ibex that mentioned earlier, there's a national reserve in Spain to put those creatures back into with relative little disturbance. Other situations, absolutely true that it's going to be very hard. So it's really a case by case, and I think that's one of the things that should be looked at when we're trying to decide which of these species to bring back.

BROWNLet's go to Luke in Bethesda, Md. Luke, you are on the air.

LUKEHi. I just was listening to your show. I'm in it a little late here, and I'm 15, and I was listening to it, and I was wondering why is it necessary to meddle with something as profound nature? Why not just it run its course?

BROWNWell, do our guests feel that nature is being meddled with, or that this is all part of the story, including our involvement as human beings?

SHAPIROI think this is something that we've touched on a bit, and I think it's worth reiterating that, sure, over the course of Earth's history, probably more than 99 percent of any species that's ever existed is now extinct. The difference that's going on today is that this is not a natural course of events. In the last thousand years or so, the rate of extinction has increased dramatically, and it's not natural. It's all anthropogenic. It's because of increased hunting pressures, changing the environment that we live in, and this is not the natural course. So it's time for us to think about what we should do about it.

BROWNWell, do you -- let me pose this question back at you then. If this is not part of the natural course of events, where do human beings fit in? I mean, a moment ago I said are we not part of the story? It may not be a course that is pretty for some of us humans to observe as we watch other creatures around us fail because of our activities, but hasn't that happened in the past? Don't other animals hunt other animals to extinction and then possibly collapse themselves, and then the cycle begins anew.

SHAPIROSure.

BROWNSo is this not...

SHAPIROBut we are the first of all of these animals that have the capacity to be able to think about ways that we might be able to stop our actions and reverse them.

BROWNThat's a very important point. Jamie.

SHREEVEYeah.

BROWNThanks Beth.

BROWNI'd just like to point out to the caller, good question. But we are professional meddlers with nature. We've been doing it for thousands of years. That's what we do. We just have always been doing it thoughtlessly. Every time you put in parking lot you're meddling with nature if there was something there that was natural before. And you could bring it all the way back to invention of agriculture. The difference that we're doing now is trying to meddle thoughtfully, and I think that's a major difference. We're trying to correct things.

BROWNIt's being mindful in a sense...

SHREEVECorrect.

BROWN...of the impact that we are having. And rather than having dominion over nature working within it perhaps, is that another way of putting it?

SHREEVEI would say yes. Proactively taking a stand on changing our relationship to nature to be where we're not meddling with it just in the course of our daily activities, but we're meddling in it in a way, if we can still use that word, in such a way that we can have very positive long-term effect, and take that as our primary responsibility in our relationship to nature.

BROWNBriefly, does anyone have any insight into whether there's concern about paleo-modern hybrids if they were to be created, escaping from the laboratory and mixing with species in today's natural world? We have a question about that from Richard via email. Anyone want to respond to that? Is there a concern that if a species were brought back, and it's a hybrid, that then we would get yet something else if it were to escape its environment? Is there a possible negative outcome?

BROWNI'll take unless Beth...

BROWNSure Jamie.

SHREEVEI think we're -- again, these species are changing all the time anyway. When you -- the genetic diversity is being processed and reprocessed all the time. If we were to introduce something that has, you know, been done carefully and is pretty much, you know, a variation on an extinct species, I mean, I -- there are concerns that perhaps for instance it may be carrying a virus that was in the paleo species, but that it was immune to, but that the extinct species is not. And these are concerns that would have to be addressed. But by and large, I think we're not really talking about bringing flying GMOs back in, you know, into the world where they're going to wreak havoc.

BROWNAll of you -- all of our guests here, and we have just a moment or so for this, participated in a TEDx program hosted by National Geographic last week in D.C. What goals do you have for creating a framework to oversee and perhaps regulate the extinction projects? We've had several questions about that over the course of the hour. How do you govern something like this? How do you keep things safe? Within the next half minute or so, let's try to go around the circle and answer that. Ryan, what are your thoughts/

PHELANYes. Revive & Restore, as an outgrowth of our TEDx De-extinction conference, really hopes to continues to keep this dialogue, first and foremost, in the public domain, to increase the level of transparency around the science of where these efforts are taking place, how we can all learn from them, how we can create the necessary safeguards, if that is what is required, how do we collaborate, if that can be encouraged, and so we're really looking at continuing to move this dialogue into the future.

BROWNBeth Shapiro, very briefly here.

SHAPIROThat's just -- to notice that, a lot of the reactions that we get to this are based on fear of the unknown, and all we're trying to do is make sure that the thing that is known about, that people do think about even write frightening fiction books about, is actually out there on the table so we can have a fruitful and productive discussion. This the way to make this safe.

BROWNThanks. And Jamie Shreeve?

SHREEVEIt's an ongoing discussion and we'll leave it at that.

BROWNTo be continued.

SHREEVEYes.

BROWNAnd thanks very much all of you. Jamie Shreeve, Beth Shapiro, Ryan Phelan, our guests as we've been talking about de-extinction. I'm Paul Brown and this is "The Kojo Nnamdi Show" on WAMU 88.5.