Scientific publications about DNA structure-function and PCR technique in Costa Rica : A historic view ( 1953-2003 )

The spreading of knowledge depends on the access to the information and its immediate use. Models are useful to explain specific phenomena. The scientific community accepts some models in Biology after a period of time, once it has evidence to support it. The model of the structure and function of the DNA proposed by Watson & Crick (1953) was not the exception, since a few years later the DNA model was finally accepted. In Costa Rica, DNA function was first mentioned in 1970, in the magazine Biología Tropical (Tropical Biology Magazine), more than 15 years after its first publication in a scientific journal. An opposite situation occurs with technical innovations. If the efficiency of a new scientific technique is proved in a compelling way, then the acceptance by the community comes swiftly. This was the case of the polymerase chain reaction, or PCR. The first PCR machine in Costa Rica arrived in 1991, only three years after its publication. Rev. Biol. Trop. 52(3): 417-421. Epub 2004 Dic 15.

The first issue of Tropical Biology Magazine, in July 1953, was not only a very important date for our scientific community, but a few months earlier that same year was published the model of the structure and function of DNA (Watson and Crick 1953).One reason to publish a journal in Costa Rica was the perception of some researchers to use our tropical regions in order to study Biology and make a contribution to the scientific community.How did these events impact the scientific work in our country?In the first years of Revista de Biología Tropical, a clear trend dominated to publish works on the Natural History and Taxonomy fields, because most of the researchers belonged to those areas.In the 35 th anniversary of the journal Monge-Nájera and Díaz (1988) detailed the main subjects of the scientific output.The most frequent subjects were animal taxonomy, human biology -including medicine-, ecology and animal behavior (Monge-Nájera and Díaz 1988).Later for its 50 th anniversary, a special issue was dedicated to review the contributions in main stream areas like Biomedicine (Gutiérrez 2002), Entomology (Hanson 2002), Marine Biology (Cortés and Nielsen 2002), Paleontology (Aguilar 2002), and Botany (León 2002).However, it was hard to trace a line of scientific publications in those former days related to molecular biology or in general DNA techniques.Another major practical discovery with a broad use in Biology was the developing of the first polymerase chain reaction by K.B. Mullis in 1983, but published until 1985(Saiki et al. 1985), and the use of the Thermus aquaticus polymerase (Saiki et al. 1988).
In general terms, I searched for most of the publications from national researchers dealing with nucleic acids topics, covered in national and international journals indexed in public databases.In a review, León (1993) mentioned that recombinant DNA techniques have been introduced to our region for diagnostic and research purposes.Since that time in Costa Rica, those techniques have extended into universities and higher education centers (University of Costa Rica, National University, Technological Institute of Costa Rica, and CATIE), public institutions (Judicial Investigation Organism, San Juan de Dios Hospital, Children's Hospital, INCIENSA) and some private companies.I found two types of publications which mention DNA or genetic material and articles with experimental work on DNA (i.e.chromosomes, expression) or RNA (viruses).A mention about DNA or genetic material does not necessarily imply an experimental approach on DNA or RNA.A similar case could be extrapolated to the proposal of the DNA model elaborated by Watson and Crick in 1953.For example, Francis Crick had never performed an X-ray diffraction experiment (Fresco 1998).In Costa Rica, the first paper which made a DNA citation to explain the genetic of hemoglobinopathies was done in 1965 (Bickers et al. 1965).The next paper with a DNA-mention, dealing with clinical epidemiology about hemoflagellates, was published six years later (Zeledón 1971).In conclusion, we can say that it took about 12 years to mention the word DNA and their implications in a scientific journal.And it is no surprise that both quotes were in the biomedical field.
The first publication on experimental DNA work in a scientific journal was submitted by León (1969).The paper was the presentation of karyotypes of 21 species of anurans.I consider this work the start point of the cytogenetics in Costa Rica because it inspired other persons to continue using this technique.The implementation of karyotypes to study snakes in Costa Rica was a fertile field in terms of publications.A detailed protocol was published by Taylor and Bolaños (1975).Karyotypes of coral snakes (Gutiérrez andBolaños 1979, 1981), vipers (Gutiérrez et al. 1979, Solorzano et al. 1988) and snakes (Gutiérrez et al. 1984) were published mainly by researchers from the Clodomiro Picado Institute.Many years later, karyotype has been used as a tool to study some human diseases (Castro Volio et al.1993, Solís et al. 2000, Castro Volio 2004a, b).This means scientific knowledge was transmitted.
Important to mention were the publications related to DNA structure-function from national researchers as part of their Ph.D. thesis outside of Costa Rica.The first paper was presented by P.E.León during his visit to the University of Oregon (U.S.A.) dealing with ribosomal genes (Wen et al. 1974).Only two years later, G. Macaya working at the University of Paris published papers about eukaryotic genome organization (Thiery et al.1976, Macaya et al 1976).A few years later, a hypothesis about the meaning of plumbed chromosomes was proposed by Espinoza et al. (1980).In the decade of the 1980's at least two M.Sc.students worked on DNA structure in Leishmania mexicana (Ryan 1982) and in genome organization of the salamander Bolitoglossa subpalmata (Alegría 1988).Lately, Mora et al. (1996) published the first description in Costa Rica of the eukaryotic genome organization of a tropical organism.
As mentioned above, the PCR technique opened a new dimension in biological research.Since the PCR publication in 1989, some researchers working in contact with international laboratories were interested to apply that technique.Only one year after the publication of the PCR technique, the first researcher in Costa Rica to use the PCR was E. Moreno, for sequencing the 16S RNA of Brucella abortus (Dorsch et al. 1989).He and the German collaborative group in Kiel performed a reverse transcription, a PCR and a dideoxy sequence reaction to obtain the sequence of the 16S RNA.Finally, the first PCR experiment in Costa Rica was performed in the virology laboratory of Veterinary School in the Universidad Nacional between 1990 and 1991 (L.L. Rodríguez, personal comm.) and from that work a manuscript was presented to an international journal (Rodríguez et al. 1993).However, the first papers using the PCR technique in Costa Rica were published in the issue of Revista de Biología Tropical by C. Sierra (2001) and Morera et al. (2001).C. Sierra worked on the genetic relationship among the pigs from Coco's Island, supported by the Wildlife Program of the National University.Morera et al. (2001) performed a population genetic analysis with DNA markers, which encouraged the introduction this technology in the Costa Rican Judicial branch.
Since these pioneer publications many other researchers have contributed with their work on DNA and related techniques through the last two decades.Their contributions cover different areas; some examples are in molecular bacteriology (Morera-Brenes et al. 1994, Bustamante et al. 2003, Arrieta et al. 2004, Xet-Mull et al. 2004), in human genetics (Lynch et al. 1997, Leal et al. 2001, Morales-Cordero et al. 2001, Morera et al. 2001, Venegas et al. 2003), in plant genetics (Céspedes et al. 2003, Muñoz et al. 2004, Valdez et al. 2004), and molecular zoology and protozoology (Lizano et al. 2000, Lamar and Sasa 2003, Sittenfeld et al. 2004).ACKNOWLEDGMENTS I apologize to many researchers that I could not include in this note.Thanks to P.E.León, L.L. Rodríguez and J. Mora Urpí with their excellent memory and for their valuable comments.