Model organisms have been given special status in biological research by the National Institutes of Health and researchers themselves. But does being a model organism guarantee an increasing publication trend? Using the ISI "Web of Knowledge" database, we compiled publication data for each of the organisms included on the NIH canonical list of model organisms: rat, mouse, Drosophila, Arabidopsis, Chicken, Zebrafish, S. cerevisiae, S. pombe, Xenopus, Neurospora, Daphnia, C. elegans, and Dictyostelium. (See graphic).
While mammalian models clearly predominate in publication rates, rat publication rates have been in decline since 1996 while mouse publication rates have increased. Established organisms, such as Drosophila, yeast, and chicken, have either increased or maintained steady publication rates.
Some more recent model organisms have shown dramatic increases, including Arabidopsis, Zebrafish, and C. elegans. Some newly designated model organisms, including S. pombe, Neurospora, Daphnia, and Dichtyostelium, have maintained steady but relatively low numbers of publications per year. Xenopus, the only "non-genetic" model organism, seems to have declining publication numbers since 1996.
These trends raise numerous questions: what explains the differences in publication rates between model organisms such as Arabidopsis as compared to Dictyostelium? Why do some established model organisms continue to increase their publication numbers (e.g., Drosophila), while rates for others such as S. cerevisiae remain about the same, and others (e.g., Xenopus) decline? Are publication rates a function of amount of funding, standardization of the organisms, social organization, or some other sociocultural or historic factors?
We invite your comments on the trends and possible explanations.
Data for this analysis of publication trends was extracted from ISI Web of Knowledge: Science Citation Index Expanded (SCI-EXPANDED) -- 1900-present using a title search. All searches were conducted on August 15, 2010. Search terms were as follows: Rat (Rat or Rattus or Rattus rattus), Mouse (Mouse or Mus musculus or M. musculus), Drosophila (Drosophila), Arabidopsis (Arabidopsis), Chicken (Chicken or Gallus or Gallus gallus or G. gallus), Zebrafish (Zebrafish or Danio rerio or D. rerio), S. cerevisiae (Saccharomyces cerevisiae or S. cerevisiae), Xenopus (Xenopus), S. pombe (Schizosaccharomyces pombe or S. pombe), Neurospora (Neurospora or Neurospora crassa or N. crassa), Daphnia (Daphnia), C. elegans (Caenorhabditis elegans or C. elegans), and Dictyostelium (Dictyostelium discoideum or D. discoideum).