Decifrando o "mistério dos gêmeos": vinte anos de pesquisa em Cândido Godói, Rio Grande do Sul / Solving the "twins mystery": twenty years of research in Cândido Godói, Rio Grande do Sul state

Cândido Godói (CG) é um pequeno município brasileiro localizado no noroeste do Rio Grande do Sul e é conhecido como "Cidade dos Gêmeos" devido à alta taxa de nascimentos gemelares na região. Diante de um fato tão notável, muitas explicações foram sugeridas. Entre estas teorias, a que mais recebeu atenção da mídia, mesmo sem base científica, foi a de que a gemelaridade seria fruto de experimentos de um médico nazista alemão foragido após a Segunda Guerra Mundial. A convite da própria comunidade de CG, nosso grupo de pesquisa trabalha para resolver este mistério desde 1994, analisando diferentes fatores possivelmente relacionados, em especial suas características genéticas. Aqui, nós sumarizamos os principais resultados obtidos em mais de duas décadas de pesquisa, com foco nas particularidades do processo de comunicação dos resultados, aspectos éticos e como os achados científicos naquela comunidade contribuem não apenas com a resolução de um mistério histórico e local, mas também com o estudo de outras questões, como a reprodução humana e as bases biológicas da gemelaridade. (AU)

Cândido Godói (CG) is a small town located in the northwest region of Rio Grande do Sul state which is known as "Town of Twins" because of the high rate of twin births. Many explanations have been suggested for such a noteworthy fact. The theory that has received most attention from the press, despite a lack of scientific evidence, was that twinning would result from experiments conducted by a Nazi German physician who had been a fugitive after World War II. Invited by the local community, our research team has been dedicated to solving this mystery since 1994 by analyzing different possibly related factors, especially genetic characteristics. In this paper, we summarize the main results obtained in more than two decades of research, focusing on the particular communication process of the results, ethical aspects, and how the scientific findings in that community have contributed not only to the resolution of a historical and localized mystery, but also with the study of other issues such as human reproduction and biological basis of the twinning process. (AU)

Genetic characterization and authentication of Gardenia jasminoides in different regions of China by using improved RAPD analysis.

Gardenia jasminoides is a common garden medicinal plant known for its anticancer, anti-inflammatory, anti-thrombic, anti-fibrotic, antiviral, hepatoprotective, lung-protective, renal-protective, retina-protective and neuroprotective activities. It is found in several regions of the world, including China, but information about its genetic characteristics is limited. Here, we employed an improved method of random amplified polymorphic DNA (RAPD) analysis (with increased RAMP time) to investigate the genetic link between G. jasminoides samples collected from six different regions of Southern China. Total 26 RAPD primers were selected randomly, among which 23 primers generated reproducible polymorphic amplification bands. A total of 174 bands were obtained, where each primer had amplified 5-13 bands with an average of 7.56 bands per primer. The band size ranged approximately 150-2200 bp. Cluster dendrogram was obtained based on the improved RAPD amplification profiles, which showed that the similarity coefficients among six varieties of G. jasminoides ranged 0.67-0.88. To our knowledge, this is the first report of genetic characterization of G. jasminoides using improved RAPD analysis, which may be useful for the preservation of genetic diversity and identification of Gardenia population.

Molecular analysis of an odorant-binding protein gene in two sympatric species of Lutzomyia longipalpis s.l.

Lutzomyia longipalpis s.l. is the main vector of American visceral leishmaniasis (AVL) and occurs as a species complex. DNA samples from two Brazilian sympatric species that differ in pheromone and courtship song production were used to analyse molecular polymorphisms in an odorant-binding protein ( obp29 ) gene. OBPs are proteins related to olfaction and are involved in activities fundamental to survival, such as foraging, mating and choice of oviposition site. In this study, the marker obp29 was found to be highly polymorphic in Lu. longipalpis s.l. , with no fixed differences observed between the two species. A pairwise fixation index test indicated a moderate level of genetic differentiation between the samples analysed.