Download as PDF, PPTX
![12%
[4.002]
(6%)
4860
10%
8%
Documents
6%
[6.812]
[4.416]
(4%) [9.380]
1765 (6%)
4% 1689
1528 [31.434] [3.198]*
[31.253] [5.558]
(22%) [5.520] [4.737] [9.120]
(26%) [1.980] [8.295]
1039
891 (2%)
843 837 (2%)
2% 784 731 699 693 660 649 605
0%
PNAS
Nature
Genetika
Genetics
Development
Japan J Genetics
Cell
Genetica
Evolution
Mutation Research
Devel Biol
J Bio Chemistry
Mol Bio Cell
J Cell Biol
Embo J
Figure 13](https://image.slidesharecdn.com/globaldrosophila-110218095923-phpapp02/75/Global-drosophila-21-2048.jpg)
![Discussion
• We have analyzed 48,981 documents in the Science Citation Index (Figure 1), mostly articles
(nearly 77%) (Figure 2), the majority written in English (95%) (Figure 3).
• Temporal scientific production in Drosophila research is fairly similar (and with similar
exponential growth in both SCI and PubMed. There is a continuous increase from 1950 to 2007,
with a decrease in 2008 (Figure 1). This decrease may only be apparent and reflect a usual
delay in the indexation process. The comparison with other biological models is interesting: Zea
and Chlamydomonas show a reasonably stable publication trend (after 1970). From
approximately 1980 on, Arabidopsis and Caenorhabditis exhibit exponential growth, while
Neurospora and Dictyostelium decrease. Escherichia is the most extensively used model
organism for genetics research; from 1950 till 2007, nearly twice as many articles are published
as for Drosophila.
• One factor contributing to the extensive research with Drosophila may have been the free flow
of materials and ideas among its researchers [79]. Morgan's style of research and leadership
was distinctively focused on an experimental, rather than a descriptive approach to science.
Between 1940 and 1970 new techniques were developed, mutants increased in number and
complexity, all fairly freely shared by a gradually increasing number of investigators.
• In the 1970s and 1980s, genetics, developmental, and molecular biology came together in a
successful combination, which brought Drosophila research to a climax. Molecular biology rose
later than the other subjects, associated mostly with the ability to manipulate DNA and RNA, so
that researchers could work with individual genes that produced phenotypic alterations. E.B.
Lewis [80] studied mutations which caused bizarre transformations of the body plan: mutations
in genes in the 'bithorax complex' led to flies with two sets of wings or legs on abdominal
segments. The strangeness of the changes produced became a clue to discover the crucial role
of master control genes that program the final body plan of the organism. 23](https://image.slidesharecdn.com/globaldrosophila-110218095923-phpapp02/75/Global-drosophila-23-2048.jpg)
![• Christiane Nüsslein-Volhard and Eric Wieschaus (1980) [81] began working together with Drosophila
flies in a laboratory in Heidelberg, Germany. They systematically searched for mutant genes that
affect the formation of segments in the fly embryo. They identified a series of new genes that drive the
early development of the organism, and also were able to classify the genes into functional groups.
They showed that these genes are conserved in vertebrates. It would soon become clear that close
relatives of these genes, performing similar roles, exist in many other different organisms, including
humans. Indeed, it is now thought that more than 60 percent of the genes involved in human diseases
may have counterparts in the fly.
• An important breakthrough for manipulating the genome was made in 1982 by A.C. Spradling and
G.M. Rubin [82]. They developed a method for making transgenic flies by means of transposable
element vectors. They used this method to achieve the first rescue of a mutant phenotype in an
animal by gene transfer.
• New technologies are also being brought to bear on the study of Drosophila. Since 1999, the genome
sequence of Drosophila has been available, and researchers are using functional genomics to
investigate global patterns of gene and protein expression. The genome sequences of several other
Drosophila species have now become available, which opens up new opportunities for functional
genomics studies, looking at gene and protein expression on a large scale. Such experiments can
produce huge amounts of data, difficult to interpret, organize, and store.
• As pointed out, genetics and heredity, biochemistry, molecular biology and cell biology are the leading
research subjects in SCI. Some journals in our survey are multidisciplinary, such as Nature and
Science. We have shown that there are temporal trends with respect to research subject as well as to
model organisms and prevailing methodologies: toxicology, cell biology, and descriptive
developmental research are decreasing, while evolutionary biology, biochemistry, and molecular
biology are increasing. The most frequent terms in Drosophila research have genetics, heredity, or a
molecular connotation.
• The most cited paper, providing the complete sequence of the euchromatic region of the Drosophila
genome was published in Science in 2000, with 2,751 citations at the time of our survey.
24](https://image.slidesharecdn.com/globaldrosophila-110218095923-phpapp02/75/Global-drosophila-24-2048.jpg)
More Related Content
Global drosophila
- 1. Global Drosophila melanogasterResearch: a bibliometric analysis Michán, L; Castañeda-Sortibrán, A; Rodríguez-Arnaiz, R; Ayala, FJ Drosophila Information Service, Vol. 93 (2010), 232-243. http://www.ou.edu/journals/dis/DIS93/Michan%20232.pdf Complementary material 1
- 2. Abstract • We investigate the scientific productivity of Drosophila-related research among researchers, countries, institutions, journals, and subject areas, by a bibliometric analysis of Drosophila research from 1900 to 2008. We have searched the Science Citation Index (SCI) documents with the word Drosophila in the title. 48,981 documents were obtained from SCI 76.9% of the documents are research papers, mostly (95.2%) written in English, and (55.8%) produced in the United States. The study includes 4,600 institutions and 45,415 author names. Most prolific are 34 authors, who account for 9% of the articles published, with more than 100 research papers produced by each author. We also provide a list of the 50 most cited articles. We considered 1,648 journals; 60 of them (3.6%) published 66% of the articles. Genetics is the main journal most used for Drosophila research publications (9.9%). Genetics and heredity as well as biochemistry, molecular biology, and cell biology are the dominant research subjects. We compare research in Drosophila with 10 other organisms, frequently used as biological models: Escherichia, Saccharomyces, Arabidopsis, Zea, Neurospora, Dictyostelium, Chlamydomonas, Caenorhabditis, Schizosaccharomyces, and Danio. Escherichia coli is the most extensively used model organism for genetics research since 1950, with 94,873 documents. We analyzed 36,486 documents in detail with respect to their contents, using the indexing keywords listed in the medical subject headings (MeSH) thesaurus. 2
- 3. Materials and methods • Our search covered papers published during 1900-2008. The search was performed using the Science Citation Index (SCI) and the PubMed database. SCI was started by the Institute for Scientific Information (ISI) in 1963. It is now owned by Thomson Reuters and is available online through the Web of Science database. PubMed Central, which started in 2000, includes articles and peer-reviewed manuscripts dating back to mid the 1800s or early 1900s for some journals. These databases include many journals; provide a citation index; and the results of the queries are comparative concerning mainstream papers in scientific research. PubMed has detailed document identification by the keywords listed in the medical subject headings (MeSH) thesaurus. We accessed the Science Citation Index until 2008, in order to find out where research in Drosophila has been done. We accessed data on documents with the word Drosophila in the title of the paper, because we were interested only in documents with their main interest in Drosophila. All records were retrieved for each database and were systematized in a database; then the data sets were validated and normalized, and a quantitative analysis for each category was done: document, author, affiliation institution, country, journal, subject area (from Science Citation Index) and MeSH headings and subheadings (from PubMed). The 50 and the 10 most cited papers from Science Citation Index were identified. Journals were processed by subject (sensu SCI), Impact Factors were obtained from Journal Citation Report 2008 and core journals were identified with Bradford`s method (Bradford, 1948). The same method was used for each of ten additional biological models: Escherichia, Saccharomyces, Arabidopsis, Zea, Neurospora, Dictyostelium, Chlamydomonas, Caenorhabditis, Schizosaccharomyces, and Danio. All the information was organized with scientific, historical, and sociological points of view. 3
- 4. Results • Papers. Thetotal number of publications with Drosophila in the title was 48,981 in the Science Citation Index and 36,486 in PubMed (Figure 1). The first paper registered was published in 1905 by F.W. Carpenter . Document type and language according to the Science Citation Index are shown in Figures 2 and 3. The temporal trends of publication in Drosophila, as well as in ten other biological models are shown in Figures 4 and 5. There are 139 different subject categories in the SCI, the 16 most frequent, each with more than 1% of the total are shown in Figure 6. The temporal trends for the nine most frequent subjects are shown in Figures 7 and 8. Information about documents extracted from PubMed is in Figures 9 and 10. 4
- 5. 1800 SCI Expanded 1600 PubMed 1400 y = 4,072e0,065x 1200 Documents 1000 800 600 400 200 y= 1,704e0,070x 0 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Figure 1
- 6. Document type Article Meeting Abstract Review Note Proceedings Paper Letter Editorial Material 3% 1% 1% 0% 3% 15% 77% Figure 2
- 7. Language Japanese French 1.35% 0.89% German 0.32% Russsian 2.29% English 95.15% Figure 3
- 8. 250 Zea (7636) Neurospora (6640) Dictyostelium (6191) 200 Chlamydomonas (5646) Schizosaccharomyces (3183) Danio (973) 150 Documentos 100 50 0 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Figure 4
- 9. 3000 Escherichia (94873) Drosophila (48989) 2500 Saccharomyces (27549) Arabidopsis (18094) Caenorhabditis (5353) 2000 Documents 1500 1000 500 0 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Figure 5
- 10. 706 Behavioral Scien 782 Biotech & Microbio 1200 Biophysics 1231 Physiology 1258 Toxicology 1465 Entomology 1811 (2) 1258 Ecology 2340 (3) Evolutionary Bio Figure 6 2365 Zoology Subject Area 2482 (2) Biology 2519 (1) Neurosciences 4310 (20) Multidisciplinary 6328 (3) Develop Bio 8137 (15) Cell Bio 10907 (18) Biochem & Mol Bio 17900 (6) Genetics & Heredity 0% 5% 30% 25% 20% 15% 40% 35% 10% Documents
- 11. 600 Genetics & Heredity Biochemistry & Molecular Biology 500 Cell Biology Developmental Biology 400 Neuroscience Documents 300 200 100 0 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Figure 7
- 12. • Researchers. Wefound 45,415 author names. The 34 most prolific, each with more than 100 published articles and jointly accounting for 9% of all the papers, are shown in Table 1. There were 119 affiliation countries, 32 (2.6%) of which include each more than 100 papers, and jointly accounting for 97% of all papers. The 10 countries with most publications are shown in Figure 11. The United States was the country most represented. There were 4,600 different institutions, such as universities, departments, and corporations. The 18 most highly represented are shown in Figure 12. Table 2 lists the 50 papers with the highest citation impact. 12
- 13. Researcher Documents (48,981) Rubin, GM 220 (5) David, JR 203 Dobzhansky, T 185 Perrimon, N 184 Hall, JC 170 Mukai, T 164 Zhimulev, IF 160 Jan, YN 155 Gehring, WJ 149 (2) Jackle, H 148 Ayala, FJ 143 (1) Hoffman, AA 139 (1) Jan, LY 131 Bownes, M 126 Parsons, PA 126 Partridge, L 126 Ashburner, M 123 (2) Green, MM 122 Belyaeva, ES 122 Glover, DM 119 Levine, M 115 (1) Mahowald, AP 115 King, RC 111 Singh, BN 111 , SCR 110 Wurgler, FE 110 Korochkin, LI 109 Hartl, DL 109 Georgiev, PG 106 Kaufman, TC 103 Wu, CF 103 (1) Rosbash, M 101 Ehrman, L 101 Mackay, TFC 101 Table 1. The 34 most prolific researchers in Drosophila, each with 100 or more papers, as retrieved from the Web of Science. Numbers in parentheses are documents shown in Table 2. 13
- 14. 2005 2000 1995 1990 1985 1980 1975 1970 1965 1960 Figure 8 Year 1955 1950 1945 Evolutionary Biology 1940 1935 Toxicology 1930 Zoology Ecology 1925 1920 1915 1910 1905 100 80 70 50 40 30 20 0 90 60 10 Documents
- 15. 2626 Cloning, molecular 3381 3358 3309 2832 2778 2687 2654 Transcription, genetic Dna-binding proteins Chromosome mapping DNA Larva Gene expression regul, develop Transcription factors 4184 3517 Phenotype Genes, insect Figure 9 5319 5049 Amino acid sequence Base sequence 6838 Molecular sequence data 8548 7931 Mutation Male 9614 Female 10201 14984 Drosophila proteins 18425 Drosophila Drosophila melanogaster 31837 Animals 100% 50% 25% 0% 75% Documents
- 16. 1163 Radiation effects 1201 Methods 1408 Anatomy & histology 1524 Isolation & purification 2361 Biosynthesis 2574 Analysis 2859 Ultrastructure 2931 Drug effects Figure10 3246 Enzymology 3414 Pharmacology 3712 Chemistry 4177 Growth & development 4685 Cytology 6843 Embryology 11655 Physiology 13586 Metabolism 23265 Genetics 70% 60% 50% 40% 10% 0% 30% 20% Documents
- 17. USA France England Japan Germany Canada Spain Switzerland USSR Australia 2.9% 2.7% 3.5% 4.0% 4.0% 6.2% 6.4% 55.8% 7.2% 7.4% Figure 11
- 18. Cornell Irvine Pennsylvania Max Planck 2 Texas Zurich Wisconsin 2 N Carolina 1 Stanford 3 Institution Figure 18 San Francisco 2 Yale 3 Paris Berkeley 2 Cambridge 2 Washington 1 Harvard CNRS, France Russian Aca Sci 0 1400 1200 1000 600 400 200 800 Documents
- 19. Adams et al.(2000). The genome sequence of Drosophila melanogaster. Science, 287(5460):2185–2195. 2,751 Rubin, G. M. and Spradling, A. C. (1982). Genetic-transformation of Drosophila with transposable element vectors. Science, 218(4570):348–353. 2,184 Tautz, D. and Pfeifle, C. (1989). A non-radioactive in situ hybridization method for the localization of specific RNAs in Drosophila embryos reveals translational control of the segmentation gene hunchback. Chromosoma, 98(2):81–85. 2,126 Lewis, E. B. (1978). Gene complex controlling segmentation in Drosophila. Nature, 276(5688):565–570. 1,906 Medzhitov et al. (1997). A human homologue of the Drosophila toll protein signals activation of adaptive immunity. Nature, 388(6640):394–397. 1,752 Nüsslein-Volhard, C. and Wieschaus, E. (1980). Mutations affecting segment number and polarity in Drosophila. Nature, 287(5785):795–801. 1,727 Lemaitre et al. (1996). The dorsoventral regulatory gene cassette spatzle/toll/cactus controls the potent antifungal response in Drosophila adults. Cell, 86(6):973–983. 1,277 Spradling, A. C. and Rubin, G. M. (1982). Transposition of cloned p elements into Drosophila germ line chromosomes. Science, 218(4570):341–347. 1,228 Robertson et al. (1988). A stable genomic source of p-element transposase in Drosophila melanogaster. Genetics, 118(3):460–470. 1,153 Hammond et al. (2000). An RNA-directed nuclease mediates post-transcriptional gene silencing in Drosophila cells. Nature, 404(6775):293–296. 1,147 Ashburner, M. and Bonner, J. J. (1979). Induction of gene activity in Drosophila by heat shock. Cell, 17(2):241–254. 1,135 McDonald, J. H. and Kreitman, M. (1991). Adaptive protein evolution at the adh locus in Drosophila. Nature, 351(6328):652–654. 1,117 Xu, T. and Rubin, G. M. (1993). Analysis of genetic mosaics in developing and adult Drosophila tissues. Development, 117(4):1223–1237. 1,091 Bateman, A. J. (1948). Intra-sexual selection in Drosophila. Heredity, 2(3):349–368. 1,079 Ephrussi, B. and Beadle, G. W. (1936). A technique of transplantation for Drosophila. American Naturalist, 70:218–225. 942 Clary, D. O. and Wolstenholme, D. R. (1985). The mitochondrial-DNA molecule of Drosophila yakuba - nucleotide-sequence, gene organization, and genetic-code. Journal of Molecular Evolution, 22(3):252–271. 930 Konopka, R. J. and Benzer, S. (1971). Clock mutants of Drosophila melanogaster. Proceedings of the of Sciences of the , 68(9):2112–2116. 902 Ayala et al. (1972). Enzyme variability in the Drosophila willistoni group. IV. Genic variation in natural populations of Drosophila willistoni. Genetics, 70(1):113–139. 900 Ellisen et al. (1991). Tan-1, the human homolog of the Drosophila notch gene, is broken by chromosomal translocations in t-lymphoblastic neoplasms. Cell, 66(4):649–660. 894 Wu, C. (1980). The 5’ ends of Drosophila heat-shock genes in chromatin are hypersensitive to DNase-i. Nature, 286(5776):854–860. 872 Rock et al. (1998). A family of human receptors structurally related to Drosophila toll. Proceedings of the of Sciences of the , 95(2):588–593. 860 Giot et al. (2003). A protein interaction map of Drosophila melanogaster. Science, 302(5651):1727–1736. 853 Cavener, D. R. (1987). Comparison of the consensus sequence flanking translational start sites in Drosophila and vertebrates. Nucleic Acids Research, 15(4):1353–1360. 845 Orr, W. C. and Sohal, R. S. (1994). Extension of life-span by overexpression of superoxide-dismutase and catalase in Drosophila melanogaster. Science, 263(5150):1128–1130. 838 Ingham, P. W. (1988). The molecular-genetics of embryonic pattern-formation in Drosophila. Nature, 335(6085):25–34. 837 Akam, M. (1987). The molecular-basis for metameric pattern in the Drosophila embryo. Development, 101(1):1–22. 834 Stjohnston, D. and Nüsslein-Volhard, C. (1992). The origin of pattern and polarity in the Drosophila embryo. Cell, 68(2):201–219. 831 Ritossa, F. (1962). New puffing pattern induced by temperature shock and dnp in Drosophila. Experientia, 18(12):571–573. 829 Pelham, H. R. B. (1982). A regulatory upstream promoter element in the Drosophila hsp 70 heat-shock gene. Cell, 30(2):517–528. 807 Hahn et al. (1996). Mutations of the human homolog of Drosophila patched in the nevoid basal cell carcinoma syndrome. Cell, 85(6):841–851. 800 Lewontin, R. C. and Hubby, J. L. (1966). A molecular approach to study of genic heterozygosity in natural populations. II. Amount of variation and degree of heterozygosity in natural populations of Drosophila pseudoobscura. Genetics, 54(2):595–609. 796 (1972). Cell lines derived from late embryonic stages of Drosophila melanogaster. Journal of Embryology and Experimental Morphology, 27(APR):353–&. 785 Bhanot et al. (1996). A new member of the frizzled family from Drosophila functions as a wingless receptor. Nature, 382(6588):225–230. 758 McGinnis et al. (1984). A conserved DNA-sequence in homoeotic genes of the Drosophila Antennapedia and bithorax complexes. Nature, 308(5958):428–433. 756 Halder, G., Callaerts, P., and Gehring, W. J. (1995). Induction of ectopic eyes by targeted expression of the eyeless gene in Drosophila. Science, 267(5205):1788–1792. 737 Feany, M. B. and Bender, W. W. (2000). A Drosophila model of Parkinson’s disease. Nature, 404(6776):394–398. 729 Krauss, S., Concordet, J. P., and Ingham, P. W. (1993). A functionally conserved homology of the Drosophila segment polarity gene-hh is expressed in tissues with polarizing activity in zebrafish embryos. Cell, 75(7):1431–1444. 723 Cho, K. O., Hunt, C. A., and Kennedy, M. B. (1992). The rat-brain postsynaptic density fraction contains a homolog of the Drosophila disks-large tumor suppressor protein. Neuron, 9(5):929–942. 721 Graham, A., Papalopulu, N., and Krumlauf, R. (1989). The murine and Drosophila homeobox gene complexes have common features of organization and expression. Cell, 57(3):367–378. 719 Tkachuk, D. C., Kohler, S., and Cleary, M. L. (1992). Involvement of a homolog of Drosophila-trithorax by 11q23 chromosomal translocations in acute leukemias. Cell, 71(4):691–700. 714 Poole et al. (1985). The engrailed locus of Drosophila: structural analysis of an embryonic transcript. Cell, 40(1):37–43. 705 Ohare, K. and Rubin, G. M. (1983). Structures of p-transposable elements and their sites of insertion and excision in the Drosophila melanogaster genome. Cell, 34(1):25–35. 700 Vandewetering et al. (1997). Armadillo co-activates transcription driven by the product of the Drosophila segment polarity gene dtcf. Cell, 88(6):789–799. 695 Gu et al. (1992). The t(4-11) chromosome-translocation of human acute leukemias fuses the all-1 gene, related to Drosophila-trithorax, to the af-4 gene. Cell, 71(4):701–708. 694 Tissiere, A., Mitchell, H. K., and Tracy, U. M. (1974). Protein-synthesis in salivary-glands of Drosophila melanogaster: Relation to chromosome puffs. Journal of Molecular Biology, 84(3):389–398. 671 Ingolia, T. D. and Craig, E. A. (1982). Four small Drosophila heat-shock proteins are related to each other and to mammalian alpha-crystallin. Proceedings of the of Sciences of the United States of America-Biological Sciences, 79(7):2360–2364. 651 Smith, D. E. and Fisher, P. A. (1984). Identification, developmental regulation, and response to heat-shock of 2 antigenically related forms of a major nuclear-envelope protein in Drosophila embryos: application of an improved method for affinity 647 purification of antibodies using polypeptides immobilized on nitrocellulose blots. Journal of Cell Biology, 99(1):20–28. Elbashir et al. (2001). Functional anatomy of si RNAs for mediating efficient RNAi in Drosophila melanogaster embryo lysate. Embo Journal, 20(23):6877–6888. 641 Padgett, R. W., Stjohnston, R. D., and Gelbart, W. M. (1987). A transcript from a Drosophila pattern gene predicts a protein homologous to the transforming growth-factor-beta family. Nature, 325(6099):81–84. 639 Garcia-Bellido, A., Ripoll, P., and Morata, G. (1973). Developmental compartmentalization of wing disk of Drosophila. Nature-New Biology, 245(147):251–253. 636 19 Table 2. The 50 most cited papers according to Science Citation Index.
- 20. • Journals. A total of 1,648 journal names were obtained, 60 of them (3.6%) published 66.6% of the articles about Drosophila (Table 3). Genetics has the most publications, with 10% of the total. Cell and Nature have the highest impact (Figure 13). • The 34 authors, each with more than 100 Drosophila research papers, jointly produced almost 10% of all published papers and are the authors of 13 (26%) of the 50 most cited papers. 55.8% of all the papers had at least one North American author. After the United States and France, the most productive countries were England, Japan, and Germany. Jointly, these 5 countries account for 65% of the publications (Figure 11). The most productive institutions are the Russian Academy of Sciences, the Centre National de la Recherche Scientifique (CNRS in France), and Harvard University, each with more than 1,000 publications. Harvard had 5 (10%) of the most cited documents (Figure 12). 20
- 21. 12% [4.002] (6%) 4860 10% 8% Documents 6% [6.812] [4.416] (4%) [9.380] 1765 (6%) 4% 1689 1528 [31.434] [3.198]* [31.253] [5.558] (22%) [5.520] [4.737] [9.120] (26%) [1.980] [8.295] 1039 891 (2%) 843 837 (2%) 2% 784 731 699 693 660 649 605 0% PNAS Nature Genetika Genetics Development Japan J Genetics Cell Genetica Evolution Mutation Research Devel Biol J Bio Chemistry Mol Bio Cell J Cell Biol Embo J Figure 13
- 22. Source Title Documents % Genetics 4.860 9.92% Development 1.765 3.60% Developmental Biology 1.689 3.45% PNAS 1.528 3.12% Japanese Journal of Genetics 1.039 2.12% Nature 891 1.82% Mutation Research 843 1.72% Cell 837 1.71% Molecular Biology of The Cell 784 1.60% Genetika 731 1.49% Journal of Biological Chemistry 699 1.43% Evolution 693 1.41% Journal Cell Biology 660 1.35% Genetica 649 1.33% Embo Journal 605 1.24% Chromosoma 592 1.21% Heredity 588 1.20% Genes & Development 585 1.19% Mechanisms of Development 569 1.16% Molecular and Cellular Biology 544 1.11% Science 514 1.05% Nucleic Acids Research 497 1.01% Current Biology 491 1.00% American Naturalist 463 0.95% Genetical Research 446 0.91% Molecular & General Genetics 442 0.90% Experientia 436 0.89% Journal of Neurogenetics 430 0.88% Hereditas 390 0.80% Journal of Insect Physiology 387 0.79% Journal of Neuroscience 368 0.75% Biochemical Genetics 356 0.73% Gene 340 0.69% Journal of Cell Science 317 0.65% Molecular Biology And Evolution 317 0.65% Behavior Genetics 312 0.64% Neuron 300 0.60% Journal of Experimental Zoology 270 0.55% Journal of Molecular Biology 252 0.51% Journal of Cellular Biochemistry 243 0.50% American Zoologist 236 0.48% FEBS Letters 234 0.48% Biochemical And Biophysical Research Communications 233 0.48% Journal of Heredity 214 0.44% FASEB Journal 209 0.43% Journal of Genetics 207 0.42% Russian Journal of Genetics 202 0.41% Developmental Genetics 194 0.40% Developmental Cell 192 0.39% European Journal of Cell Biology 192 0.39% Journal of Molecular Evolution 192 0.39% Canadian Journal of Genetics and Cytology 191 0.39% Biophysical Journal 189 0.39% Doklady Akademii Nauk SSSR 185 0.38% Journal of Experimental Biology 184 0.38% Journal of Neurobiology 176 0.36% Development Genes and Evolution 167 0.34% Insect Biochemistry and Molecular Biology 166 0.34% Wilhelm Roux’s Archives of Developmental Biology 166 0.34% Animal Behaviour 164 0.33% Table 3. Core journals (60, with 66.6% of all published papers) of Drosophila research. 22
- 23. Discussion • We have analyzed 48,981 documents in the Science Citation Index (Figure 1), mostly articles (nearly 77%) (Figure 2), the majority written in English (95%) (Figure 3). • Temporal scientific production in Drosophila research is fairly similar (and with similar exponential growth in both SCI and PubMed. There is a continuous increase from 1950 to 2007, with a decrease in 2008 (Figure 1). This decrease may only be apparent and reflect a usual delay in the indexation process. The comparison with other biological models is interesting: Zea and Chlamydomonas show a reasonably stable publication trend (after 1970). From approximately 1980 on, Arabidopsis and Caenorhabditis exhibit exponential growth, while Neurospora and Dictyostelium decrease. Escherichia is the most extensively used model organism for genetics research; from 1950 till 2007, nearly twice as many articles are published as for Drosophila. • One factor contributing to the extensive research with Drosophila may have been the free flow of materials and ideas among its researchers [79]. Morgan's style of research and leadership was distinctively focused on an experimental, rather than a descriptive approach to science. Between 1940 and 1970 new techniques were developed, mutants increased in number and complexity, all fairly freely shared by a gradually increasing number of investigators. • In the 1970s and 1980s, genetics, developmental, and molecular biology came together in a successful combination, which brought Drosophila research to a climax. Molecular biology rose later than the other subjects, associated mostly with the ability to manipulate DNA and RNA, so that researchers could work with individual genes that produced phenotypic alterations. E.B. Lewis [80] studied mutations which caused bizarre transformations of the body plan: mutations in genes in the 'bithorax complex' led to flies with two sets of wings or legs on abdominal segments. The strangeness of the changes produced became a clue to discover the crucial role of master control genes that program the final body plan of the organism. 23
- 24. • Christiane Nüsslein-Volhard and Eric Wieschaus (1980) [81] began working together with Drosophila flies in a laboratory in Heidelberg, Germany. They systematically searched for mutant genes that affect the formation of segments in the fly embryo. They identified a series of new genes that drive the early development of the organism, and also were able to classify the genes into functional groups. They showed that these genes are conserved in vertebrates. It would soon become clear that close relatives of these genes, performing similar roles, exist in many other different organisms, including humans. Indeed, it is now thought that more than 60 percent of the genes involved in human diseases may have counterparts in the fly. • An important breakthrough for manipulating the genome was made in 1982 by A.C. Spradling and G.M. Rubin [82]. They developed a method for making transgenic flies by means of transposable element vectors. They used this method to achieve the first rescue of a mutant phenotype in an animal by gene transfer. • New technologies are also being brought to bear on the study of Drosophila. Since 1999, the genome sequence of Drosophila has been available, and researchers are using functional genomics to investigate global patterns of gene and protein expression. The genome sequences of several other Drosophila species have now become available, which opens up new opportunities for functional genomics studies, looking at gene and protein expression on a large scale. Such experiments can produce huge amounts of data, difficult to interpret, organize, and store. • As pointed out, genetics and heredity, biochemistry, molecular biology and cell biology are the leading research subjects in SCI. Some journals in our survey are multidisciplinary, such as Nature and Science. We have shown that there are temporal trends with respect to research subject as well as to model organisms and prevailing methodologies: toxicology, cell biology, and descriptive developmental research are decreasing, while evolutionary biology, biochemistry, and molecular biology are increasing. The most frequent terms in Drosophila research have genetics, heredity, or a molecular connotation. • The most cited paper, providing the complete sequence of the euchromatic region of the Drosophila genome was published in Science in 2000, with 2,751 citations at the time of our survey. 24
- 25. Figure Legends • Figure 1. Temporal trend in global Drosophila publications, 1905-2008 (from WoS and PubMed). • Figure 2. Document type in Drosophila research according to the Science Citation Index. • Figure 3. Document language in Drosophila research according to the Science Citation Index. • Figure 4. Temporal trend and total number of publications in Drosophila and four other biological models. • Figure 5. Temporal trend and total number of publications in five biological models. • Figure 6. The 16 most frequent subjects and number of documents (% most cited papers). • Figure 7. Temporal trends of Drosophila research for the most frequent subject. • Figure 8. Temporal trends of Drosophila research for four additional subjects. • Figure 9. Most frequent MeSH headings from PubMed: number and percent of documents. • Figure 10. Most frequent MeSH subjects from PubMed: numbered percent of documents. 25