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<v Bill Kurtis>A computer is taking us deep inside the cells of a human body, traveling <v Bill Kurtis>through the mast chemicals strands of DNA which determine whether <v Bill Kurtis>a fertilized cell will become a man or woman, dog <v Bill Kurtis>or cat. This is where the secrets of our existence lie. <v Bill Kurtis>The answers to what make our bodies what they are and how they work. <v Bill Kurtis>Our New Explorers are about to embark on a journey inside this amazing world <v Bill Kurtis>to search for a gene in which just 1 pair of molecules out of thousands <v Bill Kurtis>has changed. Mutated. <v Bill Kurtis>Gone wrong. <v Bill Kurtis>What they find will tell them whether this little girl's future lies in a world of sound <v Bill Kurtis>or silence. <v TV Announcer>Major funding for The New Explorers is provided by Amoco celebrating
<v TV Announcer>the adventure of scientific discovery for the year 2000 and beyond. <v TV Announcer>Additional funding is made possible by Waste Management Inc., providing <v TV Announcer>recycling and other waste services around the world. <v TV Announcer>And by Duracell embracing the power of science education, <v TV Announcer>the source of future technology and innovative growth. <v TV Announcer>Duracell, the copper top battery. <v Bill Kurtis>Hello, I'm Bill Kurtis. Here in the heart of Catago, Costa Rica, there was once <v Bill Kurtis>a beautiful church. <v Speaker>[bell tolls] <v Bill Kurtis>When a terrible earthquake destroyed it, the devout people of Cartago rebuilt it stone <v Bill Kurtis>by stone. But when a second earthquake wrecked it, the people said it is <v Bill Kurtis>God's will. And they left it a beautiful ruin. <v Speaker>[chorus sings] <v Bill Kurtis>Since the 18th century, the descendants of Manuel Monge have suffered a strange
<v Bill Kurtis>affliction. Half of every generation has gone deaf. <v Bill Kurtis>Like the earthquakes, some said it, too, was God's will. <v Bill Kurtis>For 9 generations, the Monheit family has lived, worked, and flourished in the town <v Bill Kurtis>of Cartago, Costa Rica. <v Bill Kurtis>From old documents, geneticists have reconstructed the family tree <v Bill Kurtis>through almost 3 centuries. <v Bill Kurtis>The Monge children are born hearing, but for half of them, life is a slow <v Bill Kurtis>journey into silence. <v Bill Kurtis>First, they lose the low tones, the rumble of the trucks, the sounds of thunder <v Bill Kurtis>and drums. <v Bill Kurtis>By 20, the middle tones, the familiar sounds of the human voice disappear.
<v Bill Kurtis>And by about age 30, all is silence. <v Bill Kurtis>Yet despite this enormous handicap, this remarkable family has lived and <v Bill Kurtis>prospered for 9 generations, earning its way, creating jobs <v Bill Kurtis>and small businesses. <v Bill Kurtis>But what went wrong all those generations ago? <v Bill Kurtis>That's what these 2 scientists want to find out. <v Bill Kurtis>One in Central America, the other in North America. <v Bill Kurtis>They're working to piece together the puzzle. <v Bill Kurtis>They determined that the Monge deafness is caused by a single gene. <v Bill Kurtis>Now they have to find it inside another world. <v Bill Kurtis>Their journey will take them into a single human cell, then into the nucleus <v Bill Kurtis>of the cell, and finally into the vast tangled chemicals called DNA,
<v Bill Kurtis>the blueprint of life. <v Bill Kurtis>23 pairs of chromosomes containing all the genes that can dip into <v Bill Kurtis>a soup of chemicals and build a human being. <v Bill Kurtis>It's 1 of the great discoveries of the century. <v Bill Kurtis>Just as 26 letters can spell all the words of our language or 10 digits <v Bill Kurtis>make every number in the universe, so just 4 chemicals arranged <v Bill Kurtis>in pairs repeated 3 billion times spell out the formula <v Bill Kurtis>for a human being. <v Mary-Claire King>In the Monges, we suspect that there's just a single based pair, <v Mary-Claire King>a single element of DNA that's changed that distinguishes <v Mary-Claire King>the Monges' gene from everyone else's gene at this local <v Mary-Claire King>on chromosome 5 [fade out]. <v Bill Kurtis>Mary-Claire King, 1 of the world's leading geneticists, is working on the Monge gene <v Bill Kurtis>from her University of California Berkeley lab. <v Bill Kurtis>King and her researchers are closing in on the gene of breast cancer, on genetic factors <v Bill Kurtis>in AIDS, in the wasting disease of lupus.
<v Bill Kurtis>Even using genetics to reunite kidnaped children, victims of Argentina's dirty <v Bill Kurtis>war, with their families. <v Bill Kurtis>Her partner in Costa Rica, once her student, is geneticist Pedro Leon, <v Bill Kurtis>who first brought the Monge family to the world's attention. <v Pedro Leon>We know that in about 1713, an ancestor to the whole <v Pedro Leon>family was deaf and transmitted the deafness to at least 3 of his children, 2 of <v Pedro Leon>which have descendents today with affected members that we are studying. <v Bill Kurtis>So that ancestor had a mutation in the gene? <v Pedro Leon>That ancestor had a mutation in the gene. <v Bill Kurtis>The Monges seem to fly on the face of evolutionary theory. <v Bill Kurtis>A powerful, harmful mutation, a dominant gene for deafness, has not <v Bill Kurtis>stopped them. <v Pedro Leon>They're very successful in dealing with their- with their social life. <v Pedro Leon>They all marry unaffected people and- and they have many kids. <v Bill Kurtis>And this is the secret of the Monge family success.
<v Bill Kurtis>The way for generations they have beaten evolutionary law. <v Bill Kurtis>Watch. <v Monge Grandfather>[speak Spanish] <v Bill Kurtis>The grandfather can hear. <v Bill Kurtis>So for now, can his grandson. <v Bill Kurtis>Yet he insists that the child watch him as he speaks. <v Bill Kurtis>For 9 generations, every descendant of Manuel Monge has learned <v Bill Kurtis>almost from birth to read lips. <v Bill Kurtis>Since no one knows which child will become deaf, each is taught to watch faces, <v Bill Kurtis>to exaggerate expressions when speaking in the family. <v Bill Kurtis>And even the youngest learn that for a grandmother who is deaf, there is no need <v Bill Kurtis>to make sounds. <v Mary-Claire King>I think for this family, they take deafness as a-
<v Mary-Claire King>as a given in the same way one does black hair. I mean, this is not by any <v Mary-Claire King>means the worst thing that could happen to them. <v Speaker>[speaking Spanish] <v Bill Kurtis>The Monges refuse to learn to sign. <v Bill Kurtis>They say their children must learn to live among the hearing. <v Bill Kurtis>And even when Pedro tries to talk them into using hearing aids, it's an uphill fight. <v Bill Kurtis>[speaking Spanish in background] Pedro isn't trying to get the father to use the hearing <v Bill Kurtis>aid, his hearing is gone. <v Bill Kurtis>But for his teenage daughter, it might mean a few more precious years of hearing. <v Pedro Leon>If they don't do it early on, they will never get used to them and they will reject them. <v Pedro Leon>And that's been our experience. So I think our modest contribution to their <v Pedro Leon>well-being is to convince them that early on a hearing aid will allow them to continue <v Pedro Leon>to go to school, to pursue their professions and so on. <v Bill Kurtis>In Cartago, everyone knows the Monge descendants.
<v Bill Kurtis>They're almost a point of civic pride. <v Bill Kurtis>So Katia and Gabriella Cassada's coworkers automatically adapt to the lip-reading <v Bill Kurtis>mode. <v Katia Cassada>Everybody is very nice with me. <v Katia Cassada>They accept me the way I am and I accept everybody the way people are. <v Katia Cassada>[speaking Spanish in background] For me, human beings don't have to be the same. <v Katia Cassada> And God put this in me. <v Katia Cassada>And for other people, they are blind or they have other problems. <v Katia Cassada>But for me, this is the 1 I have. <v Bill Kurtis>In Katia's generation, <v Bill Kurtis>the Cassadas got a bad roll of the genetic dice. <v Bill Kurtis>Katia, Gabriella, and their brother Javier, all inherited <v Bill Kurtis>the gene. All are going deaf. <v Bill Kurtis>Gabriella communicates with her boyfriend by reading his lips. <v Bill Kurtis>Javier wonders whether his 1-year-old daughter Anna will be spared.
<v Bill Kurtis>He's not sure he wants to know. <v Bill Kurtis>Anna and the next generation are why the family has volunteered to become <v Bill Kurtis>a collective genetic guinea pig. <v Pedro Leon>They will say it openly, they will say me we are doing this for our kids, not for us. <v Pedro Leon>We don't- we don't expect to cured. You don't even know that we want to be cured. <v Pedro Leon>But for our kids, yes. <v Bill Kurtis>It may be that geneticists think a little more about kids, their own kids than <v Bill Kurtis>the rest of us do. <v Bill Kurtis>For Pedro Leon, the fact that his 3 children can all hear, simply hear, <v Bill Kurtis>is a continuing miracle. <v Bill Kurtis>For Mary-Claire King. <v Mary-Claire King>My daughter is- is my proudest accomplishment and anything I do- anything I do <v Mary-Claire King>in- in genetics with my brain doesn't compare remotely to me the importance of my child. <v Mary-Claire King>Um, yeah, my daughter's got great genes, but what I can <v Mary-Claire King>control and what I can give her is a good environment.
<v Mary-Claire King>So to me, the idea of inheritance is not limited to genetic inheritance, <v Mary-Claire King>both for the best things that we can- that we can think about in life, <v Mary-Claire King>we can- we transmit information to the next generation genetically and culturally. <v Mary-Claire King>And to the extent that I can do that with <v Mary-Claire King>my biological child and with these kids in my lab, I think I will have done something <v Mary-Claire King>kind of useful. [background chatter] <v Henriette Raventos>So I have 1 tube for each DNA sample. <v Henriette Raventos>The 11 are 11 of 1 family. <v Henriette Raventos>So we have a father, mother and 9 kids. <v Henriette Raventos>Families like this [fade out] <v Bill Kurtis>Dr. Henriette Raventos, call her ?Jettie? <v Bill Kurtis>At Pedro Leon's lab at the University of Costa Rica, she now <v Bill Kurtis>has the astonishing ability to predict, with better than 90 percent accuracy, <v Bill Kurtis>which children will become deaf and which will not.
<v Bill Kurtis>That's because more than 100 Monge descendants, men, women, children <v Bill Kurtis>have contributed blood samples, their own DNA. <v Bill Kurtis>And the geneticists have been able to isolate the 1 chromosome out of 23 pairs <v Bill Kurtis>that contains the mutated gene, chromosome 5. <v Henriette Raventos>[background chatter] <v Pedro Leon>Over a year ago, we were able to show that all affected members of the <v Pedro Leon>family shared a fairly large region of chromosome 5. <v Pedro Leon>As we increase the sample size and involved new branches of the family, we were able <v Pedro Leon>to narrow that region even more. <v Pedro Leon>And, of course, as we increase our sample size, eventually we narrow the region to a <v Pedro Leon>relatively small, small segment of chromosome 5, which is shared by all the affected <v Pedro Leon>members, but it's not present in the unaffected. <v Bill Kurtis>Katia, Gabriella, and Javier all contributed their DNA <v Bill Kurtis>and all show the signature pattern on chromosome 5.
<v Bill Kurtis>And that in turn leads to the next crucial moment in this scientific detective story. <v Bill Kurtis>Prediction. <v Henriette Raventos>So now I have the DNA in- in the tubes. <v Henriette Raventos>Now I'm going to make a mix that will contain all the ingredients <v Henriette Raventos>necessary for the PCR. <v Bill Kurtis>The same method that located the deafness gene on chromosome 5 just a year ago <v Bill Kurtis>now gives scientists the power to predict who in the family will go deaf. <v Bill Kurtis>The secret is a new genetic technique called PCR, polymerase chain reaction, <v Bill Kurtis>which can turn one tiny fragment of DNA into thousands of identical copies. <v Henriette Raventos>This is the PCR machine. <v Henriette Raventos>The first thing it will do is heat up the samples <v Henriette Raventos>a- to a temperature where the DNA will- the 2 bands will open <v Henriette Raventos>up. What the PCR does is that <v Henriette Raventos>if you have 1 molecule of DNA, after 1 cycle,
<v Henriette Raventos>you'll have 2. After the second cycle, you'll have 4. <v Henriette Raventos>After the third cycle, you'll have 8. <v Henriette Raventos>And so on. <v Bill Kurtis>A geometric progression. <v Henriette Raventos>Right. So at the end of the 25 cycles, you'll have <v Henriette Raventos>thousands of copies just of that small window. <v Bill Kurtis>I can see the little [fade out]. <v Bill Kurtis>With thousands of copies of the DNA from mother, father, and 9 children, Jettie <v Bill Kurtis>drops the samples into tiny wells in a gel and passes an electric current <v Bill Kurtis>through them. DNA has a slight negative charge, so each part will move through <v Bill Kurtis>the gel at a different speed depending on its weight. <v Bill Kurtis>And by comparing DNA from more than 100 Monges, hearing and <v Bill Kurtis>deaf, these scientists now know which lines in the gel betray <v Bill Kurtis>that strange and powerful gene, the Monge deafness. <v Henriette Raventos>This is the gell that has been already run around 18 hours and ?it does <v Henriette Raventos>stain?. So we can see now the amplified regions.
<v Bill Kurtis>Well, let's see what we have. <v Henriette Raventos>In this case, we can tell only that this 1 will become deaf <v Henriette Raventos>and this 1 will not become deaf. <v Bill Kurtis>Now, what about little Anna? Can you predict if she will become deaf? <v Pedro Leon>We can predict with about 95 percent certainty whether Anna will be deaf <v Pedro Leon>or not. I don't know if they want to know and I'm not sure that <v Pedro Leon>we want to do it until we're certain that the family is prepared to deal with that <v Pedro Leon>knowledge appropriately and not uh change their behavior negatively towards <v Pedro Leon>any of the kids that might be deaf later on. <v Bill Kurtis>It's also difficult, isn't it, to tell someone they're going to be deaf and not be able <v Bill Kurtis>to tell them that there's a cure? <v Pedro Leon>That's right. That's right. <v Mary-Claire King>The most serious ethical dilemma that we face in human genetics now <v Mary-Claire King>is the gap between being able to predict who will develop various <v Mary-Claire King>conditions, which we can do now. We can do that for the Monges, for deafness.
<v Mary-Claire King>We can do that for many families for breast cancer. <v Mary-Claire King>We can do that for many, many conditions and our ability to actually do something <v Mary-Claire King>about that. The critical question is, how do you close the gap? <v Mary-Claire King>And the way you close the gap is to find the gene. <v Mary-Claire King>And when you've found the gene, then you can learn what that gene does and you can learn <v Mary-Claire King>how to change the mutant or abnormal form of that gene <v Mary-Claire King>so that you replace the abnormal product with a normal product. <v Bill Kurtis>For the Monges, the next step is to find out how the mutated gene makes them <v Bill Kurtis>go deaf. Does it affect the bones of the middle ear? <v Bill Kurtis>The drum? The auditory nerve? <v Bill Kurtis>Pedro Leon has brought 3 of the family members to San Francisco for some advanced <v Bill Kurtis>ear testing to find out. <v Bill Kurtis>But before the tests, there is a sight-seeing.
<v Bill Kurtis>Beneath the Golden Gate, Katia, her cousin Adolfo, and his 6-year-old <v Bill Kurtis>son Eric pause for pictures. <v Bill Kurtis>They've never been outside Costa Rica. <v Bill Kurtis>Eric can still hear the thunder and the crash of the long Pacific rollers. <v Bill Kurtis>To Katia, at 22, they're a distant hiss. <v Bill Kurtis>To Adolpho, past 30, something even less. <v Robert Jackler>And what we can see is 3-dimensional view of the eardrum. <v Robert Jackler>Gracias. [fade out]. <v Bill Kurtis>At the University of San Francisco hearing lab, Dr. Robert Jackler begins work on Adolfo. <v Robert Jackler>And as expected, the eardrum looks normal. <v Robert Jackler>There's the drum. There, can you see? [laughs] <v Bill Kurtis>Eric is being prepped for a CAT scan.
<v Bill Kurtis>This giant x-ray machine will make 3-D drawings of his entire ear <v Bill Kurtis>structure. <v Speaker>[speaking Spanish]. <v Bill Kurtis>Because the organs of hearing are so intimately linked with the semicircular canals of <v Bill Kurtis>balance, the San Francisco researchers want to see whether there's any effect on Katia's <v Bill Kurtis>equilibrium. <v Robert Jackler>Can you see the eyes jumping? It tells us that her inner ears are <v Robert Jackler>sensing motion. And it's the motion of the fluid within the balance canals that <v Robert Jackler>is continuing its momentum and that uh it lasts for a few moments. <v Robert Jackler>So what it tells us is, although she has a very severe hearing loss, is that the balance <v Robert Jackler>side of the inner ear seems to be functioning, at least to some degree. <v Bill Kurtis>Later, much more delicate tests will confirm. <v Bill Kurtis>There's nothing wrong with Monge ears except that they go deaf. <v Doctor>Eric, ?decir? Mesa.
<v Eric>Mesa. <v Doctor>?Decir? Cinco. <v Eric>Cinco. Aqua. <v Bill Kurtis>Through 2 grueling days, the doctors mix standard hearing tests with <v Bill Kurtis>the most sophisticated techniques. <v Bill Kurtis>This is a scan of Eric's brainwaves to see whether sound ever reaches his auditory <v Bill Kurtis>nerve. Fascinating for the scientist. <v Bill Kurtis>A bit dull for a 6-year-old. <v Doctor>It looks like at this particular frequency, he does have some hair cells <v Doctor>or some nerve cells that are still firing and still working in a pretty <v Doctor>good manner. <v Doctor>This test procedure is just fantastic. <v Doctor>The information this is giving me 2 years ago, we never could have gotten on <v Doctor>anybody. <v Bill Kurtis>The bottom line for the Monge deafness, deep inside the cochlea, the inner <v Bill Kurtis>ear organ of hearing, lie rows of tiny nerves called hair cells, thousands
<v Bill Kurtis>of them. And Manuel Monge's descendants, the delicate hair cells stop responding <v Bill Kurtis>to sound, either because something goes wrong with them or because the transparent <v Bill Kurtis>fluid in which they live and work thickens up. <v Bill Kurtis>That is the legacy of the Monge mutated gene. <v Bill Kurtis>Now it's up to the scientists to find a way to switch it back on. <v Mary-Claire King>For us as geneticists, there's both the hope and the absolute commitment <v Mary-Claire King>to closing the gap between being able to predict who will <v Mary-Claire King>develop 1 or another condition that- that we're mapping and <v Mary-Claire King>being able to offer a cure or absolute prevention. <v Bill Kurtis>While they're in California, Katia, Adolfo, and Eric go to visit Mary-Claire King and <v Bill Kurtis>see the Berkeley lab where she's trying to map the gene that is taking away their <v Bill Kurtis>hearing.
<v Bill Kurtis>Here in this freezer, the DNA of Manuel Monge's descendants, cloned now, <v Bill Kurtis>so the supply will never run out. <v Bill Kurtis>Short fragments of chromosome 5 from more than 100 family members. <v Bill Kurtis>Half of them carry the Monge gene. <v Mary-Claire King>[speaking Spanish] <v Bill Kurtis>This is the key. The genetic map of more than 100 descendants <v Bill Kurtis>of Manuel Monge. <v Mary-Claire King>[speaking Spanish] <v Bill Kurtis>6-year-old Eric sees himself a square because he's a male. <v Bill Kurtis>A blackened square because he has the gene. <v Bill Kurtis>[Spanish in background] In each set of parents, <v Bill Kurtis>1 blacked-out symbol, the carrier of the Monge gene. <v Bill Kurtis>[Spanish in background] <v Bill Kurtis>And every blackened symbol shares the same short strip of DNA marked with a
<v Bill Kurtis>box, perhaps a dozen genes on chromosome 5, which include <v Bill Kurtis>the Monge deafness gene. <v Bill Kurtis>Mary-Claire King and Pedro Leon are now in the homestretch. <v Bill Kurtis>Like geographers, they have begun to chart the territory of the Monge gene. <v Bill Kurtis>Next, they will try to find a method in both its normal and mutated <v Bill Kurtis>form that they say will be the great breakthrough, the beginning of the end, <v Bill Kurtis>perhaps, of this journey through 3 centuries and 2 worlds. <v Mary-Claire King>Then we'll know what this gene does normally. <v Mary-Claire King>And of course, we'll know what it does in its mutant form. <v Mary-Claire King>And those 2 pieces of information will be absolutely critical to <v Mary-Claire King>being able to offer a cure or to being able to prevent deafness from <v Mary-Claire King>beginning in the first place. <v Bill Kurtis>These New Explorers believe they've gotten hold of a sort of scientific philosopher's
<v Bill Kurtis>stone, that the same techniques hold the key to curing and <v Bill Kurtis>preventing a host of devastating genetic ills. <v Bill Kurtis>Perhaps sooner than we think. <v Mary-Claire King>Gene therapy is not, to me, a matter of manipulating what <v Mary-Claire King>our children will be like. Gene therapy is the use of genetics <v Mary-Claire King>for medical purposes. The use of genetics to both determine <v Mary-Claire King>what the best kinds of medicines will be and the use of genetics to- <v Mary-Claire King>to actually introduce those medications to the organism, to <v Mary-Claire King>ourselves, to fix whatever it is that's gone wrong. <v Mary-Claire King>Working on the soma, on the body, of the individual with the illness is going to be <v Mary-Claire King>revolutionized in the next 5 years. And I anticipate that we'll be <v Mary-Claire King>using it for- for the Monge deafness, for Huntington's disease, for breast cancer, <v Mary-Claire King>for a wide variety of important human traits.
<v Bill Kurtis>The gift of the Monges may be a gift to all of our children, not just their own. <v Bill Kurtis>And what about Anna? Pedro Leon knows whether or not he is fated to go deaf, <v Bill Kurtis>but her family has not yet asked. <v TV Announcer>Major funding for The New Explorers is provided by Amoco, celebrating <v TV Announcer>the adventure of scientific discovery for the year 2000 and beyond.
<v TV Announcer>Additional funding is made possible by Waste Management Inc., providing <v TV Announcer>recycling and other waste services around the world. <v TV Announcer>And by Duracell embracing the power of science education, <v TV Announcer>the source of future technology and innovative growth. <v TV Announcer>Duracell, the copper top battery. <v TV Announcer 2>A videocassette and accompanying teacher's guide are available for each episode of The <v TV Announcer 2>New Explorers. To order, call 1 800 6 2 1 0 6 6 0, or write <v TV Announcer 2>The New Explorers, 1 5 1 8 1, Route 58 South, Oberlin, Ohio, <v TV Announcer 2>4 4 0 7 4. <v PBS Announcer>This is PBS.
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Series
The New Explorers. Series III
Episode Number
No. 309
Episode
Spiral of Silence
Producing Organization
WTTW (Television station : Chicago, Ill.)
Contributing Organization
The Walter J. Brown Media Archives & Peabody Awards Collection at the University of Georgia (Athens, Georgia)
AAPB ID
cpb-aacip-526-z02z31px2n
If you have more information about this item than what is given here, or if you have concerns about this record, we want to know! Contact us, indicating the AAPB ID (cpb-aacip-526-z02z31px2n).
Description
Episode Description
This episode centers around the geneticists studying the Monge family deafness, a gene mutation that has been passed down through hundreds of descendants, causing a large percentage of the family to lose their hearing by the time they reach adulthood. The New Explorers segment explains how the advancement in this research could lead to breakthroughs regarding gene therapy and prevention and/or treatment of other serious gene mutations. Featuring scientists Mary-Claire King, Pedro Leon, Henriette Raventos, and Robert Jackler, as well as members of the Monge family.
Broadcast Date
1993
Asset type
Episode
Media type
Moving Image
Duration
00:28:37.033
Credits
Producing Organization: WTTW (Television station : Chicago, Ill.)
AAPB Contributor Holdings
The Walter J. Brown Media Archives & Peabody Awards Collection at the University of Georgia
Identifier: cpb-aacip-6695a6f15c5 (Filename)
Format: U-matic
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Citations
Chicago: “The New Explorers. Series III; No. 309; Spiral of Silence,” 1993, The Walter J. Brown Media Archives & Peabody Awards Collection at the University of Georgia, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC, accessed March 29, 2024, http://americanarchive.org/catalog/cpb-aacip-526-z02z31px2n.
MLA: “The New Explorers. Series III; No. 309; Spiral of Silence.” 1993. The Walter J. Brown Media Archives & Peabody Awards Collection at the University of Georgia, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC. Web. March 29, 2024. <http://americanarchive.org/catalog/cpb-aacip-526-z02z31px2n>.
APA: The New Explorers. Series III; No. 309; Spiral of Silence. Boston, MA: The Walter J. Brown Media Archives & Peabody Awards Collection at the University of Georgia, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC. Retrieved from http://americanarchive.org/catalog/cpb-aacip-526-z02z31px2n