Agenesias dentarias: en busca de las alteraciones genéticas responsables de la falta de desarrollo

En conjunto, las agenesias dentarias son la malformación cráneofacial más frecuente. Su prevalencia alcanza el 20% en la dentición permanente, y su expresión puede variar desde la ausencia de una sola pieza, generalmente un tercer molar, hasta la de toda la dentición. En la pasada década, los estudios de ligamiento genético y biología molecular han permitido identificar algunas mutaciones responsables de distintos patrones de agenesias dentarias sindrómicas y no sindrómicas. Dichas mutaciones se encuentran en genes clave para el desarrollo de la dentición, como los que codifican a los factores de transcripción MSX1, PAX9 y PITX2, la proteína de señalización EDA y su receptor EDAR. Los estudios que están en curso podrían derivar en nuevas clasificaciones que relacionen los fenotipos observados con el defecto genético subyacente. De esta manera, se posibilitaría un diagnóstico previo a la aparición del defecto somático, que técnicas como la terapia génica o la ingeniería de tejidos y órganos, podrían llegar a solucionar.Tooth agenesis are the most common craniofacial malformations. Its prevalence in permanent dentition reaches 20% and its expressivity ranges from only one tooth, usually a third molar, to the whole dentition. Genetic linkage and molecular biology studies have allowed, in the last decade, the identification of mutations responsible for some patterns of syndromic and nonsyndromic tooth agenesis. The mutated genes are key genes for the development of dentition, like the ones that encode the transcription factors MSX1, PAX9 and PITX2, the signalling protein EDA and its receptor EDAR. Current research would lead to the development of new classifications of tooth agenesis that took into account both the phenotypes and the genetic background. This would allow an early diagnosis of the condition, before the development of the somatic defect, that could eventually be repaired with gene therapy or tissue and organ engineering

Geographic distribution and conservation status of Caiman latirostris (Crocodylia, Alligatoridae) in Uruguay

Populations of Caiman latirostris are known to occur in Uruguay but their geographic distribution remains uncertain. This work presents anupdate of the species distribution and conservation status in Uruguay. Surveys conducted by the authors confirmed the presence of this species in the previously known distribution range of northwestern Uruguay, where it seems to be widespread and relatively abundant in contrast to earlier reports. We report new localities for C. latirostris, most relevant being those of the Cebollatí and Tacuarí Rivers, and the Pelotas, India Muerta and San Miguel stream basins, which significantly expand its distribution through important wetlands in the eastern part of the country. The overall distribution is coincident with different landscape types, where lagoons, artificial impoundments, livestock waterholes, rivers, streams, creeks and marshes are inhabited by caiman. Illegal non-commercial hunting was detected all over the country

Lipomatous tumour in the endangered toad <i>Melanophryniscus montevidensis</i>(Anura: Bufonidae) from Uruguay

We communicate the finding of a subcutaneous neoplasia in a female specimen of the toad Melanophryniscus montevidensis (Bufonidae) from Uruguay. The lesion extended from the cephalic to the abdominal region, and both gross and microscopic features were typical of lipomas. This is to our knowledge the fourth case reported in amphibians.Asociación Herpetológica Argentin

Advertisement and release calls in Neotropical toads of the Rhinella granulosa group and evidence of natural hybridization between R. bergi and R. major (Anura: Bufonidae)

The Rhinella granulosa group currently includes 12 species distributed eastern to the Andes, from Panama to central Argentina. We studied bioacoustic features of the advertisement calls in seven of these species: Rhinella azarai, R. bergi, R. centralis, R. dorbignyi, R. fernandezae, R. major, and R. merianae. In addition, we analyzed the release calls of R. azarai, R. bergi, R. dorbignyi, and R. fernandezae. The advertisement calls consisted of long trills, composed by notes with a variable pulse number (2 800x600 -8) that was characteristic of each species. The release calls consisted of a single note, pulsed or not. Both advertisement and release calls clearly varied between species, except for R. dorbignyi and R. fernandezae. The study of specimens sharing exosomatic characters with R. bergi and R. major from a syntopy area, which presented intermediate spectral and temporal call parameters, confirmed natural hybridization between these two species.Fil: Guerra, Cecilia. Instituto de Herpetología, Fundacion Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Baldo, Juan Diego. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Rosset, Sergio Daniel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Borteiro, Claudio. Museo Nacional de Historia Natural; UruguayFil: Kolenc, Francisco. Museo Nacional de Historia Natural; Urugua

Geographic distribution and apparent decline of <i>Crotalus durissus terrificus</i> (Laurenti, 1768; Serpentes, Viperidae) in Uruguay

The rattlesnake Crotalus durissus terrificus (Laurenti, 1768; Serpentes, Viperidae) is a rare species in Uruguay, where it reaches the southern boundaries of its distribution. The most recent distribution map available for this species in Uruguay is based on a few specimens that were collected during the 1950s and 1960s. Herein, we make a comprehensive account of rattlesnake records in this country obtained from herpetological literature and other bibliographic sources, specimens accessioned in herpetological and non-specialized local collections, and new information gathered during field surveys.Asociación Herpetológica Argentina (AHA

Geographic distribution and apparent decline of <i>Crotalus durissus terrificus</i> (Laurenti, 1768; Serpentes, Viperidae) in Uruguay

The rattlesnake Crotalus durissus terrificus (Laurenti, 1768; Serpentes, Viperidae) is a rare species in Uruguay, where it reaches the southern boundaries of its distribution. The most recent distribution map available for this species in Uruguay is based on a few specimens that were collected during the 1950s and 1960s. Herein, we make a comprehensive account of rattlesnake records in this country obtained from herpetological literature and other bibliographic sources, specimens accessioned in herpetological and non-specialized local collections, and new information gathered during field surveys.Asociación Herpetológica Argentina (AHA