neil degrasse tyson (host/astrophysicist,american museum of natural history): on this episode of nova sciencenow: the swamp creaturethat everyone fears... mark e. siddall (american museum of naturalhistory): he's not going to bite you. neil degrasse tyson: he started to bite me! mark siddall: come on. neil degrasse tyson: ...the slithery, slimyleech. mark siddall: he did not. neil degrasse tyson: he was hanging on. mark siddall: that was his back sucker, nothis mouth sucker.
uh, oh. neil degrasse tyson: but now these flexiblebloodsuckers are winning new fans in the world of microsurgery. thomas clark (accident victim): the leechessaved my finger. the part of my finger that was dying started coming back to life. neil degrasse tyson: and the big question... jill tarter (center for seti research): arewe alone? humans have been asking it forever. neil degrasse tyson: for more than 40 years,we've been trying to "tune in" to an alien station.
seth shostak (center for seti research): we'relooking for a signal somewhere on the radio dial that they might be broadcasting intospace. neil degrasse tyson: now, hundreds of newradio dishes... andrea kissack (correspondent): wow! thatis very flash gordon. neil degrasse tyson: ...are expanding thesearch for intelligent life somewhere else in the universe. jill tarter: the probability of success isdifficult to estimate, but if we never search, the chance of success is zero. neil degrasse tyson: also, if you're lookingto spy on life at the bottom of the sea, submarines
are not the answer. soenke johnsen (duke university): it's gotlights flashing, motors whirring, and then you come up to some animal, 5 inches away,and say, you know, "act natural." neil degrasse tyson: so this biologist cameup with a new kind of camera. and it's working, revealing some weird and wonderful creatures. edith widder (ocean research & conservationassociation, inc.): i was just wild. i couldn't believe it. every time we put this thing down we see somethingnobody's ever seen before. neil degrasse tyson: all that and more, onthis episode of nova sciencenow.
leechesneil degrasse tyson: hello, i'm neil degrasse tyson, your host of nova sciencenow. you know,in the old days, centuries ago, barbers were considered medical professionals. insteadof a shave and a haircut, for two bits, what you'd get was the cutting-edge treatment ofthe day, and that was bloodletting. and sometimes they did it, not with razors,but with a tiny little helper. modern medicine is not generally into bloodletting,but, strangely enough, in some cases, surgeons have come to rely once again on this talentedlittle creature. ladies and gentlemen, it turns out the leechis back! so how....you just look for ponds whereveryou find them and...
mark siddall: well, they have to have a certaincharacter. neil degrasse tyson: i wasn't quite sure whatto expect, when biologist mark siddall, my colleague from the american museum of naturalhistory, led me through the woods into a muddy swamp. mark siddall: it's not too bad. neil degrasse tyson: but i suspected it mightbe just kind of gross. this is nasty; let the record show. are wegetting sucked on right now? mark siddall: not likely to be being fed onjust yet. normally, it takes them a little while to realize we're here. they respondto movement in the water first.
neil degrasse tyson: within a few minutes,hungry leeches tracked us down and were swimming right towards us. mark siddall: there's one right there, rightthere, right there in the water. neil degrasse tyson: do i grab him? mark siddall: yup. it's a beautiful, beautifulmacrobdella decora, literally, "decorated leech." they have orange polka dots that godown the back. neil degrasse tyson: unlike mark, the squirmything's body decoration was the last thing on my mind. mark siddall: he's not going to bite you.
neil degrasse tyson: you can't blame me forgetting a little squeamish. after all, aren't these the bloodsucking creatures that turnup in movies to terrorize anybody who wanders into fresh water? humphrey bogart in african queen: if there'sanything in the world i hate, it's leeches, filthy little devils! neil degrasse tyson: once upon a time, peopleoften put leeches on their bodies on purpose. for centuries, people believed that intentionalbleeding was good for you, as a way to regulate what were called the body's "humors." mark siddall: if someone was sick, all youhad to do was rebalance the humors. you have
four humors: blood, yellow bile, black bileand phlegm. and what you needed to do was get the right balance of those, and then youwould be fine. neil degrasse tyson: in 19th century europe,the leech became the method of choice for all-purpose bloodletting. fever? try a leech.headache? stick one on your temple. overweight? never fear, leeches to the rescue. joseph upton (beth israel deaconess medicalcenter): leeching was kind of a panacea. if somebody had a black eye or a big shiner orsomething, they'd put a leech on it. that was commonplace. neil degrasse tyson: eventually, people beganto realize for a lot of the patients, all
this bloodletting wasn't really helping. andthe leech fell into disrepute, the poster child of medical ignorance. of course, it wasn't really the leeches' fault.they were just doing what they're good at, dining on your blood. mark siddall: uh, oh. neil degrasse tyson: he's got one. mark siddall: yup. neil degrasse tyson: for some reason, theleeches here seemed to prefer mark's legs to mine.
mark siddall: you got any on you, by the way? neil degrasse tyson: i don't know. will ifeel it? mark siddall: yes, you will. you will feela pinch. neil degrasse tyson: and one really choweddown on the knee of mark's assistant, sara watson. mark siddall: so what the leech is doing rightnow is it's filling up with sara's blood. neil degrasse tyson: these leeches live exclusivelyon blood, and a huge stomach is key for their survival. mark siddall: so leeches can feed six to seven,maybe eight times their unfed body weight
in blood. and because of that, what they dois they hold onto that blood in the stomach, squeeze a little bit down into the intestinesas they need it after they've finished feeding, and digest it while they're hiding under arock or going off to find a mate. neil degrasse tyson: a leech can live formonths on one good blood meal, but a full stomach creates a potential risk. left alone,the blood would soon clot and thicken. so the leech produces a powerful anti-coagulant,a blood thinner. mark siddall: the importance of this is obvious,if you're a leech, because if you fill up with blood to, like, six or seven times yourbody weight, if that blood clots inside of you, you're going to turn into a brick andfall to the bottom of the water. you can't
swim; you can't mate; you can't have young.you can't get away from predators, and it's all over. so, these anti-coagulants are extremelyimportant in terms of the leeches' survival. neil degrasse tyson: and this blood thinner,so crucial to the creature's survival, is one reason the leech's reputation has recentlybeen rehabilitated. construction worker thomas clark had seensome leeches as a kid, but a few months ago, they played a major role in his life. thomas clark: that particular day, i was doingtree work. so i was in a little bobcat(r). it's pretty simple. neil degrasse tyson: clark was using a smallloader to lift a tree trunk into a dump truck
when things suddenly went wrong. thomas clark: as i was rolling the log off,the bobcat tilted forward, came off the rear wheels. my hand came out of the bobcat, andthis part of the bobcat kissed the side of the dump truck and crushed off all these fingers.exactly right here, chu, chu, chu, chu. it just looked like i put my hand in a meatgrinder 'cause it, like, it smushed. neil degrasse tyson: clark was rushed to thehospital where surgeons struggled to rebuild his hand. amir taghinia (beth israel deaconess medicalcenter): the middle finger had the worst injury, by far. it was really just hanging off byone tendon. and it was sort of twisted on
itself. and we had to do quite a bit of surgeryto get that finger to live. neil degrasse tyson: the next day, clark'smiddle finger was not doing well. thomas clark: it was turning black, and theysaid that it was dying. so they were going to take it off. neil degrasse tyson: too much blood was cominginto his finger, but not getting out. the veins that normally carry the blood away weretoo badly damaged. amir taghinia: if there's blood going intothe finger, but there's no blood coming out of the finger, pressure builds up, and thetissues can't tolerate that. if you were to leave that state and not doing anything torelieve that pressure, relieve that tension,
relieve that outflow, the finger would die. neil degrasse tyson: it didn't look like moresurgery would fix the problem. so, even though doctors usually want to stop bleeding afteran operation, in this case, it was just the opposite. amir taghinia: so your next option is to useleeches. thomas clark: i was actually kind of, like,"cool." you know, i was like, you know, "whatever works. i don't want to lose anything, youknow. so, if it's going to work, let's do it." neil degrasse tyson: leeches were broughtin to feed on his finger and suck out the
extra blood. thomas clark: every time my heart beat, itwas like the leech was sucking with the beat of my heart, and it was like a pump. it waslike "bum-bum, bum-bum." neil degrasse tyson: as the leech sucks, itreleases that powerful blood thinner into the finger, which prevents clotting. amir taghinia: the leech is interesting. itinjects a blood thinner, called herudin, into the soft tissues around that area. so whenthe leech gets full and falls off, the finger continues to bleed. that buys you time, thatprocess. neil degrasse tyson: with a few days of leeching,the finger can naturally grow new veins and
resume healthy blood circulation. thomas clark: it was almost instant. you couldtell that it was working, because my...the swelling was going down. the open wounds wereactually healing. and i could actually feel a pulse in my finger. and the blackness startedgoing away. and, like, the part of my finger that was dying started coming back to life. joseph upton: when you're in a situation whereyou've already done everything that you can technically do, and then you're still havingproblems, actually, the leeches are very valuable. they're incredibly valuable. neil degrasse tyson: thomas clark's leechtherapy worked. though he hasn't regained
full function of his hand, his fingers wereall saved. thomas clark: i definitely wanted to keepmy hand and all fingers, because the human body's got ten fingers, not nine. so it meansa lot. it does. the leeches saved my finger, no doubt about it. amir taghinia: they're really indispensablefor what we do. and there would be many a finger's lopped off if it weren't for leeches. neil degrasse tyson: the leech's comebackdelights biologist mark siddall, but his appreciation goes far beyond its medical usefulness. i don't mind him crawling on me, as long asi know when he's about to bite.
leeches are a kind of worm, and there arehundreds of different species living all over the world. mark siddall: he's trying to find a placeto feed on me. there are terrestrial leeches, there are freshwater leeches, there are marine leeches. there's just this huge diversity of form, color, patternand even of behavior. and most of them are not very specific, interms of what they'll feed on, but some of them are. some of them are very specific tofish, and there's even one in africa that lives exclusively in the rectum of hippopotamus. neil degrasse tyson: eww.
mark siddall: yes, well, there was a paperwritten called, "leeches ride the tunnel of love," because they mate there. neil degrasse tyson: you sure? leeches have been crawling and swimming aroundearth for hundreds of millions of years. for siddall, these graceful creatures are fascinating,even beautiful, despite their taste for blood. mark siddall: leeches are unnecessarily maligned.they don't take more blood than you can reproduce by yourself. and you know what? unlike a mosquitoor a black fly, they don't transmit any parasites. and quite frankly, if you took some time tohave a look at them, you'd see just how pretty they are. i know most people don't reallythink about conserving leeches, but just like
any group of organisms on the face of thisplanet, wouldn't it be just a little bit colder and darker without them? search for etneil degrasse tyson: ever wonder what the chances really are of finding a needle ina haystack? think they're about as good as finding space aliens? the search for intelligent life beyond earthhas been going on now for 40 years. some folks figure, "hey, if they haven't found it bynow, it's probably not there." but as correspondent andrea kissick reports, compared to needlehunting, looking for alien life in all the billions of possible places out there is much,much harder.
andrea kissack: okay, imagine you're at thebeach. in order to figure out if there are fish in the ocean, you dip an empty glassinto the water and look inside...no fish in the glass, well, there must be no fish inthe ocean. not too logical, is it? but that's exactly the type of reasoning that's plagueddr. jill tarter for years in her long search for intelligent life in our galaxy. astronomers like tarter began searching foralien intelligence about four decades ago. in that 40 years, they've only managed tosearch 1,000 star systemsã³1,000 glasses of waterã³while an unexplored cosmic ocean layright in front of them. jill tarter: forty years needs to be put inthe context of how big the universe is, how
enormous this cosmic haystack is that we'retrying to search through. and, so, we've just begun. andrea kissack: jill knows a little somethingabout seti, the search for extra-terrestrial intelligence. she's the current director ofthe center for seti research, in mountain view, california. like many seti scientists,she was drawn into the search by the early work of astronomer frank drake. drake looked at the makeup of our galaxy andcreated an equation to determine the likelihood that other intelligent life exists. the equationoffered a simple framework for modeling the problem, taking into account things like thefraction of stars with orbiting planets, the
percentage of planets that go on to developintelligent life, and the length of time that an intelligent race lasts. the results wereclear: scientifically, the odds are pretty good that we are not alone. but if you're hunting for e.t., where do youstart? what would the sign of a technically sophisticated alien culture look like? it could look something like this. these television and radio signals are examplesof the electromagnetic waves we've been leaking into space for over 80 years. that means anyplanet within 80 light years of earth is receiving them. but tv and radio are only a small part of the electromagneticspectrum.
although astronomers use the term "radio waves,"they're generally talking about any wavelength longer than a microwave. so the radio frequencyspectrum is huge, much wider than the visible light spectrum. and signals like this are simple to generate,easily pierce dust and atmospheres, and carry well over vast distances. that's why setiscientists believe alien cultures might be leaking them, just like we are. in 1979, as a young graduate student, jilltarter joined the hunt for these telltale signals. jill tarter: i was so enthralled by the ideathat i lived in the first generation, ever,
of human beings that could try and answerthe "are we alone" question by doing an experiment, rather than just asking the priests and thephilosophers what they believed. andrea kissack: by the early 1990s, with nasafunding, tarter was heading up the search at the largest facility in the world, thearecibo radio telescope, in puerto rico. tarter became the poster child for seti. even hollywoodembraced her. tarter is generally thought to be the inspiration for ellie arroway, thecharacter played by jodi foster in the classic science fiction movie contact. it seemed the golden age of seti had arrived.then, in 1993, congress abruptly shut off all federal seti funding. but that wasn'tthe end. today, nearly 15 years later, something
big is happening in this remote valley nearhat creek, california. seti's luck may be about to change. the radio telescope dishes behind me signalthe beginning of what many believe will be a seti renaissance. and if there is to bea breakthrough, the new allen telescope array is the best bet. the reversal of seti's fortune has largelybeen made possible by a $25 million grant from paul allen, one of the founders of microsoft.on october 11, 2007, allen "pushed the silver button," bringing the first 42 radio disheson-line. when completed, the allen telescope array will consist of 350 separate dishes.together they can operate as a single "virtual"
dish, over 2,700 feet across, making it oneof the largest and most sensitive radio telescopes in the world. it will be the fastest toolever built to hunt for signals of extra terrestrial intelligence. senior seti astronomer seth shostak tellsus how this new telescope will work. seth shostak: well, andrea, to understandhow we're trying to find e.t., you have to understand the technique we're using, andthat is to look for signals in what's called the electromagnetic spectrum. that's a lotof greek, but all it really means for us is the radio dial. we're looking for a signal,somewhere on the radio dial, that they might be broadcasting into space. let me show youhow this works. i'll just turn that on. okay.
now, you notice that, if i just turn the dialhere, you hear static everywhere? andrea kissack: yeah, like white noise. seth shostak: that's just all natural noise.i mean, galaxies and hot gas between the galaxies, and pulsars and quasars, they all make radionoise, and it's everywhere on the dial. but here...wait a minute...hear that squeal?and then there's the station. all that energy...it's at one spot on the dial. nature does not makesignals that are restricted to one spot on the dial, in general. it just doesn't do that. andrea kissack: so that's intelligent life? seth shostak: that's intell...
andrea kissack: ...depending on your musicaltaste. seth shostak: it's definitely intelligence. andrea kissack: since the cosmos just don'tmake narrow, focused signals like this, finding one would be an almost certain sign of analien culture. so what is it about this new array that makesit more likely to succeed? jill tarter: the allen telescope array, basically,is all about speed. we can look at more than one star at once. and so, whereas, in thelast decade, we looked at about a thousand stars, in the next decade, we'll look at amillion. andrea kissack: that's because the allen array'sfield of view, the area of sky it sees at
one time, is much larger than any other telescope.and it can capture millions of frequencies from multiple star systems, simultaneously.basically, the allen telescope array is a seti hot rod with seti astronomers at thecontrols, 24/7. seth shostak: so here you can see where therubber really meets the road for the individual antennas. andrea kissack: wow! that is very flash gordon. seth shostak: indeed it is. in fact, the waythis thing works...it's really dead simple. the radio waves from the sky come in, theybounce off that 20-foot diameter reflector, and then they bounce off this somewhat smallerone here, in the front of the antenna, and
then they come into this feed. so this isthe thing that actually collects the radio waves and turns them into electrical signals,and in fact, down the pedestal, under the ground and back to the control room. andrea kissack: so a huge swath of the universecomes right into this room. seth shostak: yeah, it does, actually. theantennas send everything they collect from the cosmos into this room. it comes in rightback here. so all those data come in here, and then we put it together. andrea kissack: so how is this different thanthe seti of old? seth shostak: well, the fundamental differencehere is simply the amount of data you can
handle, and that's just the march of technology.the first seti experiment, back in 1960, one channel of the radio. here we've got 100 millionchannels coming in. andrea kissack: the sheer scale of the searchis almost impossible to imagine. remember, in our galaxy alone, there are about 300 billionother suns, many with orbiting planets. and beyond that, lie a hundred billion other galaxiesjust like our own. even in its current configuration, the array'svirtual dish gathers nine times more information than present-day processor technology candecode. that means 90 percent of what the telescope observes is simply thrown away,at least for now. so for the next decade or two, the technology in this little room willbe playing catch-up with the dishes outside.
seth shostak: all this stuff will be replaced,in another five years, by yet faster machines, which allow us to look at more star systems,more channels, in other words: to speed up the seti search. andrea kissack: and as that search accelerates,tarter and other seti scientists are thinking about the consequences of success. jill tarter: if we detect a signal, we'lldo everything that we can at this site to make sure that it isn't our own technologythat's fooling us or that it isn't a deliberate hoax. if we get an independent confirmation,then we will, in fact, tell the world. because a signal isn't being sent to the allen telescopearray, it's being sent to the planet earth,
and the planet earth deserves to know aboutit. andrea kissack: for jill tarter, it's a scenarioshe's imagined for almost 30 years. detecting even the accidental noise, the "dial tone"of an alien culture, would finally answer one of the most ancient questions of all. jill tarter: are we alone? humans have beenasking it forever. the probability of success is difficult toestimate, but if we never search, the chance of success is zero. stem cells breakthroughneil degrasse tyson: what if i made fettucini alfredo and then decided what i really wantedwas cheesecake? could i turn one into the
other? well, maybe i could. if i could turnback time and go back to the original ingredients, then i could make something else, entirely. this idea, of turning back the clock and rebuildingsomething from scratch is the basic premise behind stem cell research, which aims to transformone kind of cell into another. correspondent chad cohen reports recent groundbreakingdiscoveries seem to be bringing them that much closer to their goal. amiel reid (sickle cell anemia patient): itfeels like a lot of people are stabbing me with knives, from the inside of my body, allthe way down to my bone. sometimes i couldn't catch my breath it was so intense.
stephanie termitus (sickle cell anemia patient):i'm in tears, basically. it's just pain everywhere, it's going through your head, your back, yourlegs, and you can't do anything about it. chad cohen (correspondent): stephanie termitusand amiel reid know the inside of children's hospital boston better than any teenager should.they both suffer from sickle cell anemia. instead of the plump, doughnut-shaped bloodcells most of us have delivering oxygen to our organs, their blood cells are sickle-shaped,"banana," as stephanie likes to say. these cells can't deliver oxygen very well, whichcauses the kids excruciating pain. amiel's mom is on a first-name basis with the hospitalstaff. lynnie reid (mother of sickle cell anemiapatient): they've given amiel pain medication,
and it doesn't take the pain completely away.it sort of numbs it. i mean, that's happened, where he's ended up in the intensive careunit for four months. so it's pretty serious. george daley (children's hospital boston):the misshapen, stiff red blood cells get sludged and clogged into the blood vessels that feedtheir organs and their muscles and their bones. and this is intensely painful. chad cohen: it's been 50 years since researchersfound the cause for those misshapen blood cells, a single change in a single faultygene. sickle cell was the first genetic disease ever identified. george daley: give me a big, deep breath.
chad cohen: yet despite decades of searchingfor cures, all we can do is treat the symptoms, or in rare cases, perform bone marrow transplants,which are dangerous and carry a high risk of rejection. george daley: and so this is a condition thatwe need a new approach for. chad cohen: lately, that new approach hasinvolved embryonic stem cells, cells that are "pluripotent," meaning they can grow intojust about any cell in the body. when they were discovered, more than a decade ago, itwas thought that stem cells could fix, not just sickle cells, but the damaged cells ofcountless diseases: parkinson's, diabetes, a.l.s. that's what's driven george daley,who also heads a stem cell lab, right across
the street from his patients. george daley: thinking about the potentialthat this has for changing the way that we not only study disease, but one day treatdisease, is really very, very exciting. chad cohen: but there's a problem. stem cells,for the most part, come from human embryos, from that time, just after sperm meets egg,when we're made up of just a few dozen cells, and the function of those cells has yet tobe determined. the main sources for the embryos are i.v.f. clinics, where surplus embryosare often discarded as medical waste. still, harvesting the stem cells destroys the embryoand for many, that's morally wrong. others believe that holding back medical progressis also wrong.
george daley: here we are, at the dawn ofthis whole new field, all this excitement, all this possibility, and yet we're workingwith one hand tied behind our back. chad cohen: but in 2007, some experimentswere conducted that many believe will finally bring the fighting to an end. japanese researchershinya yamanaka figured out a way to take an ordinary skin cell from an adult, turnback its genetic clock and transform it into the equivalent of an embryonic stem cell,no embryos required. yamanaka's motivation came when he first glimpsed human embryosunder a microscope about 10 years ago. shinya yamanaka (gladstone institute, universityof california, san francisco): i have two daughters. and i thought, "the differencesbetween those small embryos and my own daughters
are very small." chad cohen: the realization presented someconflict for him, since, as a physician, he believed that embryonic stem cells were hisbest shot at treating disease. shinya yamanaka: to me, treating patientsand saving patients is the most important thing to do. but if we can avoid the usageof human embryos, we should avoid. chad cohen: ironically, yamanaka had to useembryonic stem cells in order to find a way to do without them. he started by exploringone of their fundamental properties. virtually every cell in the human body has the samed.n.a. heart cells, liver cells, skin cells, all share the same 20,000 genes. during ourdevelopment as embryos, though, different
genes in different cells get switched on andoff, in different ways, and that's what creates all the different types of cells in our bodies.it's called cell programming. yamanaka believed if he could find the gene switches responsiblefor programming stem cells, he could flip those same switches in adult cells, like skincells, and re-program them back to the moment before their destinies were determined. shinya yamanaka: each cell has at least 20,000genes, so that means we have to find those important switches from the 20,000 candidates. chad cohen: with so many genes to choose from,so many potential combinations, the search could have been infinitely complex.
george daley: yamanaka's insight was to appreciatethat it was a very limited set of genes. and he set out to identify them. chad cohen: first he reduced 20,000 possiblegene candidates down to 100, using on-line databases. but then, the work got harder. shinya yamanaka: we spent, like, three yearsto study the function of those 100 genes. chad cohen: were there people saying, "giveup, there's no use in this?" shinya yamanaka: yeah, many people told methat this is going to be very difficult. "you will fail." chad cohen: using specially engineered mice,called knockouts, he tested each gene's ability
to make pluripotent stem cells, eliminatingthem, one by one. after more than three years, culturing hundreds of thousands of cells,yamanaka narrowed the gene pool down to 24 genes, and finally four. then came the momentof truth: getting these four painstakingly selected genes to make stem cells. he tooksome skin cells from an adult mouse, then used a virus to insert the four genes insidethem. two weeks later the skin cells in the petri dish had completely transformed. shinya yamanaka: we saw cells which lookedlike stem cells. so it was...at the moment, you know we were very, very excited, and wewere very surprised. chad cohen: yamanaka dubbed the cells "inducedpluripotent stem cells," or i.p.s. cells,
and found they were virtually indistinguishablefrom embryonic stem cells. i can't see a difference; i wouldn't expectto be able to see a difference, but... shinya yamanaka: no, we can't see differenceseither. so these embryonic stem cells and induced pluripotent stem cells are indistinguishable.they are the same cells. chad cohen: it's amazing. george daley: yamanaka's experiment was bold,some might say foolhardy. i think it's the type of experiment that would be laughed outof the room in a standard peer review study section. you would never have gotten yourgrant funded with that experiment. chad cohen: really?
george daley: and now it's probably goingto win shinya yamanaka a nobel prize. chad cohen: creating stem cells without anembryo in mice certainly made headlines in the scientific community, but less than ayear later came the news that caught the world's attention. based on yamanaka's work, threeindependent scientists, james thomson in wisconsin, george daley in boston and yamanaka, himself,transformed human skin cells into i.p.s. stem cells. it was a monumental breakthrough, andin george daley's case, the doctor even experimented on himself. dermatologist: so what we're going to be doingis just obtaining a small biopsy of the skin and...
george daley: we have a protocol where wecan have anyone walk in, roll up their sleeve...we take a very small skin biopsy, smaller thanthe eraser at the end of a pencil. dermatologist: we'll just snip this, and we'regood to go. george daley: fantastic. and those skin cells are then put right intoa petri dish, and then, within a week, all of a sudden, this huge bloom of cells appears.and then you bring into them the three or four genes that do the re-programming. what's really remarkable is that just simplyputting those genes into the cell and making them work, starts this whole process. it takesthose stable, specialized skin cells and erases
all the skin functions, and reactivates, enlivensthe embryonic functions and turns that skin cell back into a pluripotent embryonic cell.that's really... chad cohen: back in time, basically. george daley: it's back in time, i mean, it'slike a whole altered universe. i mean, it's really changed the fundamental nature of thatcell. how many times would you say you've been inthe hospital your whole life? stephanie termitus: i can't even say it'sso many; ten times a year? chad cohen: so, how long before this technologyactually helps patients like stephanie? well, some serious challenges will have to be overcomefirst.
for one thing, that virus to shovel yamanaka'sfour genes into adult cells can mutate a patient's d.n.a. and cause cancer. at least one of thefour genes is an actual oncogene; it definitely causes cancer. and a high percentage of themice created with these stem cells did develop cancer. but the promise of these cells faroutweighs their problems, and, as we speak, researchers around the world are figuringout how to safely use them. late in 2007, rudolph jaenisch, of the whitehead instituteat m.i.t, demonstrated a powerful application of i.p.s. cells. he used them to cure sicklecell anemia in mice. to do it, he first had to give the mice the disease. so you were able, basically, to give the micesickle cell disease, and use that as a model?
rudolph jaenisch (whitehead institute, massachusettsinstitute of technology): yes. these mice were highly anemic. they had just stoppedgrowing. they were very...rather small. they wouldn't gain weight, they would die early.i mean it was...it's a very faithful model of this major human disease. you would take then a skin cell from thismouse and re-program it to i.p.s. cells. chad cohen: jaenisch made the stem cells usingyamanaka's same four gene switches, but this time he removed that nasty oncogene once ithad done its job. rudolph jaenisch: so now these i.p.s. cellsthey didn't need anymore, they didn't have that oncogene. so that was useful. and thenthe next thing was we repaired the genetic
defect by gene targeting. chad cohen: jaenisch targeted that singlesickle cell mutation, fixed it, then prompted the stem cells to become blood cells and injectedthem back into the mice. since these cells came from the very same mice, they were aperfect match; there was no chance of rejection. rudolph jaenisch: and to ourã³reallyã³delight,the blood of the mouse totally normalized, and they begin to, began to gain weight. theyhave lived. as far as we know, they have no problem, so that they're totally cured, thesemice, from the sickle cell condition. chad cohen: so have these new stem cells madeembryonic stem cells obsolete? well, until we know for sure whether they can faithfullygrow into all the different cell types, the
answer is definitely no. george daley: i'm not willing to concede thati.p.s. cells will ever fully replace human embryonic stem cells. the embryonic stem cellline remains the gold standard. could you take a big deep breath? it has been the most exciting past few yearsi could imagine, in my career. and i hope that it is translated into real treatmentsfor my kids. amiel reid: my favorite subject is science. george daley: that's good! that's very good.we like to hear that. amiel reid: the fact that they can take yourown skin and turn it into something that can
cure a disease like that, it's incredible. profile: edith widderneil degrasse tyson: the bottom of the ocean is a dark and secretive place. but if youcome down here to take a look around, once you turn on a light, of course, all the interestingstuff disappears. well, in this episode's profile, we'll meetone of the world's most determined undersea spies, who's engineering new and ingeniousways to behold the mysteries of the deep. she's clearly a woman on the go. and whenher feet are not firmly on the ground, she's perfecting her sea legs out here. edie widder is a marine biologist and explorer.her quest? to understand ocean creatures and
help save their undersea world. edie widder: i think i have the best job inthe world. seventy-one percent of the planet is covered by water, we've explored less thanfive percent of the ocean, and there are so many fabulous discoveries that have yet tobe made. neil degrasse tyson: she's working on discoveringhow animals communicate using light. it's called bioluminescence. edie widder: they use it to attract food,to ward off predators, to attract mates. it's vital to their existence. neil degrasse tyson: but there's a problem.there are only two ways to study these creatures,
in their environment or in ours. both havetheir limitations. bringing them up, well, they're not exactly themselves. going to themin a submersible also has its drawbacks. soenke johnsen: it's got lights flashing,motors whirring. and then you come up to some animal, five inches away, and say, you know,"act natural." and it's not going to happen. neil degrasse tyson: so edie came up witha new kind of camera she calls the "eye in the sea." it's basically a highly sensitivewaterproof security camera on a timer. its lights are red, which most underwater creaturescannot see. to entice animals in front of the camera,edie uses smelly fish guts inside a bait box and an electronic light show that mimics theway certain animals attract prey.
peter girguis (harvard university): thereis no doubt that edie is at the forefront of her field. and this is, again, sort ofa tribute to her capacity as a scientist and, let's say, her closet engineering tendencies. neil degrasse tyson: the eye gets droppedoff on the ocean floor, via submersible. today, edie is deploying it in the bahamas. edie widder: so we're just looking for a niceflat piece of terrain that we can set it down on safely. phil: topside, our depth is 1,585, one, five,eight, five feet. we're going to attempt to deploy it here.
edie widder: now, you've got to let go atthe right moment. neil degrasse tyson: new revelations pop upevery time edie uses it. edie widder: the payoffs have been huge. imean, every time we put this thing down, we see something nobody's ever seen before. neil degrasse tyson: in the gulf of mexico,the eye recorded an amazing first: a squid, over six feet long, that is so new to science,it cannot be placed in any known family. edie widder: i screamed so loud; and i'm nota screamer. but i was just wild. i couldn't neil degrasse tyson: most recently, the eyerevealed previously unknown feeding behavior of six-gilled sharks.
edie widder: they were doing something nobody'sever seen before. they were rooting on the bottom and apparently sucking up, in the sand,these little pill bugs, these isopods. and it's a possible explanation for how thesebehemoths survive in what seems like a desert sometimes. neil degrasse tyson: the eye has allowed marinebiologists to study creatures only a mother could love, or a human like edie. she's beendrawn to other species since she was a kid. edie widder: i loved anything to do with animalsfrom a very early age. neil degrasse tyson: school, on the otherhand, wasn't quite as much fun. edie widder: i was so bored that i just tunedout everything that was being said.
neil degrasse tyson: then edie got a new leaseon learning. her parents, both mathematics professors, whisked her away on a magicalglobetrotting adventure. first stop: europe. edie widder: ...went to all these magnificentart museums, and i decided i wanted to be an artist. then we went to egypt, and i decidedi wanted to be an archeologist. and then we went to australia and saw all of these fabulousanimals, and i decided i had to be a biologist. neil degrasse tyson: one of the last stops?a fateful trip to the teeming reefs in fiji. edie widder: i just was mesmerized by allof this life everywhere i looked. and so i wanted to be a marine biologist. neil degrasse tyson: edie had found her element.
edie widder: so the family joke is, "if we'dgone from west to east instead of east to west, would i have ended up as an artist?"but i think the total lack of talent might have been somewhat of a drawback. neil degrasse tyson: and then she found asoul mate. she was in high school, when she caught husband dave's eye. dave smith (edie widder's husband): therewas an assembly, and i was sitting in there, and i saw her come down the aisle with someof her girlfriends. and she was wearing a leather skirt. and she just looked reallyhot. she was definitely fantasy stuff. edie widder: i think the leather skirt isa figment of his imagination. but, okay, we'll
keep it in the mythology. but he was a boy with a brain. he was thefirst one i'd ever met. then one of my girlfriends pointed out to me, "wow, he's got great shoulders."shoulders? really? and so we started dating. and i hate to admit it, but i married thefirst boy i ever dated. neil degrasse tyson: and they lived happilyever after...well, almost. edie widder: it turns out my poor husbandgets seasick if there's a heavy dew on the lawn. in fact, he has declared he will neverbe going to sea with me again. neil degrasse tyson: that's okay. there'slots for him to do on land. dave's an expert in high tech instruments and is pitching inwith edie's newly-founded ocean research & conservation
association, orca. edie widder: you were talking about stormwater runoff. you have to have that meteorological data. a lot of what we want to do with our new organizationis make people aware of the value of the ocean for our existence on this planet. neil degrasse tyson: to do this, edie cameup with another invention she calls kilroy. it's a monitoring device equipped with sensorsthat can track salinity, temperature, wave height, direction and speed of the current. edie widder: we can send out commands to itas well as receive information from it.
neil degrasse tyson: to send the data backto shore, kilroy just makes a call, via standard cell phone technology. they'll keep addingsensors, including some that will measure certain pollutants. edie widder: and suddenly, now, we're startingto understand what's going on. so it's not just this placid blue surface that...everythinglooks fine. we can start telling people what's really happening. neil degrasse tyson: edie is diving into anythingthat will help people understand the oceans, including a children's book series on bioluminescence. the originality of her work and her determinationto share it with the public have earned her
the prestigious macarthur award. edie widder: i never, ever would have imaginedthe kind of career i've had. it just wouldn't have occurred to me that anything like thiscould have been possible. i didn't have any such aspirations. and i still can't believemy good fortune. cosmic perspective ã± seti neil degrasse tyson: and now for some finalthoughts on the search for life in the universe. i've always wondered how we would fare, ifthe search for intelligent life in the universe were conducted by intelligent aliens in anotherstar system. suppose they used radio waves to observe us.and suppose they had super-sensitive detectors
with specially designed decoders. imaginewhat they would find. if they fell within our radio bubble, thatexpanding sphere of waves from the dawn of our broadcast technology, then the alienswould first hear our early radio programs like amos 'n' andy, as these signals passedthem by. some years later, they might decode tv programssuch as the howdy doody show. then comes the beverly hillbillies, followed by graphic imagesfrom the vietnam and gulf wars. the aliens might then look at technology markersin our atmosphere, and find high radiation areas from nuclear test blasts and globalgreenhouse warming from the burning of fossil fuels.
after all that, what else could the alienspossibly conclude, but that earth shows no signs of intelligent life? meanwhile, with the growth of internet radioand cable television, earth may one day fall silent to eavesdropping aliens, with no broadcastsignals for them to decode. they might wonder if we'd disappeared completely.but, more likely, they will conclude, as do those on earth who search elsewhere for intelligence,that the absence of evidence is not the same as the evidence of absence. and that is the cosmic perspective. and now, we'd like to hear your perspectiveon this episode of nova sciencenow. log on
to our web site and tell us what you think.you can watch any of these stories again, download audio and video podcasts, hear fromexperts and much more. find us at pbs.org. that's our show. we'll see you next time.
