Skip to main contentU.S. National Library of MedicineU.S. National Library of Medicine

Profiles in Science
Pinterest badge Follow Profiles in Science on Pinterest!

The Joshua Lederberg Papers

Interview with Joshua Lederberg [Discovery of genetic recombination] transcript of audio
(normal size jpg)
(movie icon) High resolution Quicktime (16,734,230 Bytes)
(movie icon) High resolution RealMedia (1,831,860 Bytes)

(normal size jpg)
(movie icon) Normal resolution Quicktime (12,759,818 Bytes)
(movie icon) Normal resolution RealMedia (1,830,866 Bytes)

Running Time:
1 minute, 28 seconds
1996-03-22 (March 22, 1996)
Lederberg, Joshua
Hyde, Barbara
Joshua Lederberg interview. VHS Tape 1. Beta SP timecodes 02:00:56:00 - 02:01:24:00
Reproduced with permission of the American Society for Microbiology.
Exhibit Category:
Biographical Information
Lederberg Grouping: No Epoch
Metadata Record [Transcript of Lederberg oral history videotaped by Barbara Hyde] (March 22, 1996) pdf (4,472,080 Bytes) ocr (121,340 Bytes)
Unique Identifier:
Accession Number:
Document Type:
Video recordings
Series: Audio-Visual
Folder: Videotapes
JOSHUA LEDERBERG: Well my first important discovery came about through a rather unusual process. More than almost everything else that I've ever done, it was theory driven rather than being data driven. It was theory driven in the sense that a postulate had arisen out of the course of examination of the contemporary scene, namely Avery et al had shown transfer of heritable characteristics in a bacterium. One was deeply motivated to want to know more about whether there were things like genes in bacteria. The approach that speculatively arose and how to respond to it is: could one found out that there is a possibility of genetic recombination, of crossing between bacterial cells? My work with Neurospora had given me the theoretical basis -- one was able to put together a thought experiment that said, "if bacteria can be crossed, and if you start out with two different nutritional mutants, and if they exchange with one another, they will form prototrophic genotypes, you will be able to select for them, and define their occurrence even if they happen very very rarely by a rather simple procedure -- plating the mixtures on minimal agar". So here was a case where the experimental design was worked out -- it was a theoretical postulate: does genetic recombination occur? Does it not occur? And that was all worked out in advance of ever doing the experiment.
Well somewhat to my surprise it worked very very promptly. I was rather fearful when the first positive results came in. I was worried deeply that this was going to be an artifact, that my hopes would be dashed. I didn't want to get too excited about it. I was scared. I knew it was a very important finding, but I didn't want to be out on a limb until I could be absolutely certain and I didn't want to commit myself emotionally to the consequence until then. So it was a matter of going back to the grindstone and repeating the experiment many times, doing it different ways and being sure it was a totally reliable and reproducible result. Put in every control that I could think of to be sure it had controlled for possible artifacts. Happily, with bacteria one can do these experiments, you can run two or one or two cycles a day in this kind of experimentation so within a few weeks it was possible to get a total validation of that.
All that happened almost precisely 50 years ago. I arrived in New Haven [Connecticut] in March 1946 and by early June had it completely taped down that crossing was taking place.
Metadata Last Modified Date:
Linked Data:
RDF/XML     JSON     JSON-LD     N3/Turtle     N-Triples