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EDITOR'S COMMENT

¹ Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
² UFR de Biologie, Universite Joseph Fourier-Grenoble 1, France

In the July, 1999 issue of The FASEB Journal, Volume 13, pp. 1269–1275, we published a manuscript entitled "Porcine relaxin, a 500 million-year-old hormone?" The tunicate Ciona intestinalis has porcine relaxin.

Several readers have pointed out that conclusions presented in this paper rest on PCR and microsequencing data that may be subject to misinterpretation unless rigorous and exhaustive attempts are made to eliminate contaminating signals. Critics of this work believe that adequate measures to eliminate misleading results were not carried out. The authors’ reply appears below:

Authors’ reply

The observations presented in our paper suggest that sequence comparison is not a sure way to establish genealogies. This is a tall order and the justified questions proffered by some readers, although not unexpected, are, sensu stricto, unanswerable. What is enough care? Dr. Georges has extracted gonadal and intestinal tissue from the tunicate and only the gonadal tissue contained the mRNA for relaxin. She tested ovarian tissues during the reproductive period and during the reproductively silent period, and only the ovarian tissue harvested during the spawning month produced mRNA for relaxin. These procedures have been repeated many times during several spawning seasons (about 3 years) with the same results. PCR errors would not be that consistent. Dr. Georges is an invertebrate biologist who has never worked with porcine material.

The tunicate gonads that were harvested for protein extraction never saw my colleague’s laboratory in France and were worked up here in the U.S. in acid-cleaned glassware. The implication is that two laboratories on separate continents acquired the same contaminant, once as mRNA and once as a protein! Microsequencing is a legitimate and well-established method and is quite powerful in the hands of an expert. Contamination can be a problem but it is not an insurmountable one; fear beyond reason must not be allowed to paralyze progress.

We know that our work has been done with care commensurate with the importance of this finding and hope that our result will induce some of our colleagues to look at the enormous reservoir of proteins in our marine invertebrates. Thanks to the editor for allowing us to respond to our readers.

This article has been cited by other articles:

				M. Hafner and G. Korthof Does a "500 million-year-old hormone" disprove Darwin? FASEB J, July 1, 2006; 20(9): 1290 - 1292. [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schwabe, C. Articles by Georges, D. Search for Related Content PubMed PubMed Citation Articles by Schwabe, C. Articles by Georges, D.