We analyzed 192 cystic fibrosis (CF) alleles in three Latin American countries: Mexico, Colombia, and Venezuela. Mutation screening was performed by polymerase chain reaction (PCR) and a reverse dot blot detection kit that enables determination of 16 of the most common CF mutations worldwide. Mutations were detected in 47.9% of the screened CF alleles. The most prevalent CF allele was DeltaF508 (39. 6%). The remaining 16 non-DeltaF508 detectable mutations represented 8.3% of the CF alleles. Among them, the G542X, N1303K, and 3849+10kb C>T were the most common. Although the frequency of DeltaF508 described here is lower than that reported for Caucasian populations, including in Spain, it is remarkable that mutation prevalences found in this study resemble those observed in Spain. Two of these mutations, G542X and 3849+10kb C>T, that were relevant in this analysis, have a particularly high incidence in Spanish communities. The low frequency of DeltaF508 described here may be explained by the Amerindian, Caucasian, and Black admixture that occurred in Latin America after the discovery of the New World, and also by the probable occurrence of mutations contributed by the original natives, which were undetectable in this analysis.

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Abstract:The STR (AAAAT) n within intron 1 of the TP53 locus was screened in 17 populations from 3 main ethnic groups: Europeans, Asiatics, and Africans, and from the hybrid population of Costa Rica (1968 samples). Three alleles, 126/7 (bp/copies of the repeat), 131/8 and 136/9 were the most prevalent in all populations. Other alleles rarely reached frequencies of 10% or higher. Observed heterozygosities ranged between 0.351 and 0.829. Patterns of diversity fit well with both the geographic origin of the samples and the history of the populations screened. A statistical test suggests that single-step mutational events have been the main mechanism producing new alleles at this locus. Fixation indexes (R ST ) for this marker showed an effect of population subdivision on divergence only within the Asiatic group; they were insensitive at the level of major ethnic groups as well as within Africans and within Europeans. Rev. Biol. Trop. 52(3): 645-657. Epub 2004 Dic 15.

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El presente informe da cuenta de los resultados obtenidos en una investigación enfocada en bajar el nivel de errores ortográficos luego de observar en un pretest reiteradas faltas en sus escritos. Se implementó un seminario de ortografía en el que se trabajaron estrategias de lectoescritura y actividades de motivación.  El estudio se aplicó a un grupo de 100 estudiantes de octavo grado en el distrito de Panamá. Los resultados generales muestran que en la escritura de palabras con c/s/z hubo una disminución de errores en un 13%. Se encontraron serias deficiencias en el manejo general de la ortografía. Palabras clave: ortografía, textos expositivos, textos narrativos, faltas ortográficas, estrategias. Keywords: spelling, expository texts, narrative texts, spelling mistakes, strategies.