Replica Plating Misrepresentation

Misleading: No citation

The NLM "Profiles in Science" website for Joshua Lederberg notes that Joshua Lederberg "invented" replica plating. While this is "true" technically, it is very misleading, in that it makes it appear as if only one person was involved. It also ignores the relevant history.

Exactly what was Joshua Lederberg's contribution? First, examine the omitted full citation, in the following subsection.

Misleading: Actual citation (co-author purposely omitted)

Lederberg, J., Lederberg, E. M., March 1952, "Replica plating and indirect selection of bacterial mutants", Journal of Bacteriology 63(3): 399-406

Is there a reason for not providing a citation? Do you still think that only one person invented replica plating? Is there an attempt to deceive?

Misleading: Concept vs. Implementation

In the article written by Joshua Lederberg and edited by J. F. Crow and W. F. Dove, cited below, one can find a detailed description of replica plating. It might be argued as to which of Esther M. Lederberg or Joshua Lederberg first conceived of replica plating, but it is clear that the idea of massive replication had been conceived before either of the Lederbergs devised replica plating. (E. Tatum had taught J. Lederberg to imprint colonies using sterilized toothpicks circa 1946; Visconti had used paper at Cold Spring Harbor in the late 1940s; L. Szilard and A. Novick had used the prongs of a wire brush). (See citation highlighted in yellow on p. 395.)

If the idea for replica plating wasn't Joshua Lederberg's, then what remains is how to actually implement what became known as replica plating. The implementation of replica plating requires a researcher with real expertise in experimentation, something Esther M. Lederberg was well known for (it was also well known that Joshua Lederberg lacked this ability). The ability to figure out how to implement replica plating and actually doing so was done by Esther M. Lederberg, and this was duly noted by several researchers in the lab, as documented below. That Joshua Lederberg was not particularly adept with actual experiments has also been independently documented by none other than Joshua Lederberg himself. This is also documented below.

Furthermore, documentation exists which clearly establishes that Joshua Lederberg did not have the kind of personality that would lend itself to talking with clerks in cloth stores (as he implies). The only evidence that we have that Joshua Lederberg did this, consists solely of his own statement; there are no recorded observations of this by anyone else. Documentation also exists on this website to the effect that, from a psychological point of view, Joshua Lederberg was an extremely arrogant and unpleasant person with senior research scientists. (Examine the entries for Barbara McClintock and Arthur Kornberg at When Joshua Lederberg claims that he personally went to visit fabric stores to get cloth and advice from clerks (that he looked down upon), it is simply beyond belief that this could ever take place. (See citation highlighted in aqua, page 396.) Nobody EVER observed Joshua Lederberg going to clothing stores to find the proper cloth to be used in replica plating. The only evidence is the statement by Joshua Lederberg that he did this.

Click here to see "Perspectives: Replica Plating and Indirect Selection of Bacterial Mutants: Isolation of Preadaptive Mutants in Bacteria by Sib Selection", by J. Lederberg [J. F. Crow and W. F. Dove, Eds.], Genetics, March 1989, 121, 395-399

Evidence: A Gifted Experimentalist Required

That Esther M. Zimmer Lederberg was considered to be a genius at experimental work, has been amply documented (see comments by Stanley Falkow, Eugene Nester and Allan Campbell, below). That Joshua Lederberg was not a gifted experimentalist has been noted by several researchers in Genetics. Indeed, even Joshua Lederberg himself has written this. For example, in the 1998 University of Wisconsin Oral History Interview at Rockefeller University, on page 25, paragraph 35, Joshua Lederberg notes that the gifted experimentalist Bruce Stocker immediately observed what Joshua Lederberg had overlooked:

"JL was looking at some of those plates in his lab when Bruce Stocker dropped in. The very first day Stocker arrived, he noticed some things on JL's plates that JL had overlooked."

    Evidence: Teamwork is common in scientific research

  1. Further evidence: #1
    In this 1956 interview, Esther M. Lederberg discusses her trips to fabric stores, graciously using the pronoun "we" to include spouse Joshua Lederberg. However, as pointed out above and elsewhere, if Joshua Lederberg had ever come along and participated in any discussions with fabric store personnel, his presence would have greatly inhibited any free exchange of ideas. Esther was the kind of person who encouraged nurturing discussions with anyone, regardless of their station in life; Joshua was just the opposite.
  2. .

    Evidence: Stanford Clark Memorial

  3. Further evidence: #2
    Stanford University has created a memorial walkway (Clark Walk) between the Sherman Fairchild Building (where Esther worked) and the Li Ki Shing Pavilion, commemorating several scientists and the history of the Stanford Medical School. This walk includes a memorial to Esther M. Lederberg, where Stanley Falkow notes Esther M. Lederberg's implementation of replica plating (as well as Esther M. Lederberg's discovery of lambda), and Len Herzenberg discusses Esther M. Lederberg's discovery of Fertility factor F and some of its important uses in genetics. (Lambda and Fertility factor F are discussed below.)
  4. .

    Evidence: Stanley Falkow Memorial Talk

  5. Further evidence: #3
    Dr. Stanley Falkow pointed out, Esther Lederberg also explained exactly the method to be used to "sterilize" the velveteen fabric.
  6. .

    Evidence: Stanley Falkow (personal communication)

  7. Further evidence: #4
    Dr. Stanley Falkow further elaborated upon Esther's contribution in a personal communication to Matthew Simon on July 26, 2010:
    "My objective view is that Esther and Josh worked as a team for many years. Josh, as I said at a symposium at the National Academy of Sciences in 2008, was not in my view a gifted experimentalist. Esther was. Josh had a lot of ideas but the ideas had to be proved by experiments. Esther and Norton Zinder supplied most of the actual experiments and in a number of cases their experimental observations led to their own ideas and extension of the facts and their own discoveries. The distinction between bacterial mating and a fertility factor is quite real and I agree with Herzernberg's statement you cite. As an aside, at the same National Academy Symposium which was dedicated to Josh's memory by the organizers, several speakers as well as Stanley Cohen and me pointed out Esther's contributions to the field."
  8. .

    Evidence: Allan Campbell (personal communication)

  9. Further evidence: #5
    "Who successfully implemented the technique? Here Esther at least refined the process considerably. I remember (from her and others) that she was the one who went to the fabrics store and selected velvet of the best thickness, pile, etc. to give the cleanest prints."
    (Quoting Dr. Allan Campbell, personal correspondence, 4/16/2007)
  10. .

    Evidence: Eugene Nester (personal communication)

  11. Further evidence: #6
    "I do know that Esther in all likelihood was responsible for getting the technique to actually work. She emphasized to me how important it was to use a particular kind of Italian velvet (or was it velveteen actually), so in my own mind I believe she was the key person in taking the idea to actual practice."
    (Quoting Dr. Eugene Nester, personal correspondence, 4/19/2007 and 5/15/2007)
  12. .

    Evidence: L. Cavalli-Sforza

  13. Further evidence: #7
    L. L. Cavalli-Sforza wrote to support Esther M. Lederberg's reappointment to the faculty of Stanford's Department of Medical Microbiology, listing replica plating among her many accomplishments.
  14. .

    Evidence: Ongoing Refinements

  15. Further evidence: #8
    Shortly after Joshua Lederberg received the Nobel Prize in 1958 (circa 1962-1964), Joshua Lederberg ceased to engage in actual bench level genetics research, engaging instead in full-time administration (this is pointed out on Joshua Lederberg's NLM website, in an autobiographical fragment by Bill Hayes in 1985, as well as the observations of several researchers and can be found on this website). However, Esther M. Lederberg did not cease to do research work. After Joshua Lederberg and Esther M. Lederberg were divorced in 1966, Esther M. Lederberg continued to be involved with problems associated with replica plating. Joshua Lederberg ceased being involved with replica plating. The above pieces of correspondence document Esther's concerns with replica plating, getting involved with aspects never discussed by Joshua Lederberg. Replica plating, a methodology he derided as a "homely affair" (see J. Crow article mentioned above) was never something he was much concerned with.


The first successful use of replica plating using velveteen was done by Esther Lederberg.

The method of replica plating using velveteen developed by Esther Lederberg, was found to be extremely useful. Hundreds of research papers have been written by scientific investigators (including Joshua Lederberg) who have used Esther Lederberg's implementation of replica plating. Thus many scientific researchers have effectively collaborated in making replica plating a very valuable tool, one that continues to be used. This confirms what is most often the case: that scientific research is a collaborative process, not a "single-handed" effort or (just as false) even an "almost single-handed" effort, as claimed by the NLM website for Joshua Lederberg.