Diversidad genética de materiales nativos de aguacate guatemalteco a través del marcador molecular AFLP / Genetic diversity of native Guatemalan avocado through AFLP molecular marker

El aguacate es un cultivo de consumo a nivel mundial, y según teorías recientes, se sugiere a la región de la Sierra Nevada, en California, como centro de origen y, a Guatemala, como uno de los principales centros de domesticación. Mediante caracterizaciones morfológicas se ha reportado una alta diversidad genética en el país, pero debido al comportamiento de polinización cruzada e hibridaciones interraciales, no se ha podido detallar el estado genético actual de la especie. Sin embargo, los marcadores moleculares son útiles para este tipo de estudios al enfocarse en las diferencias a nivel del ADN. Este estudio analizó la diversidad genética del aguacate nativo guatemalteco de siete poblaciones geográficas con el marcador molecular AFLP. Los datos de estructura poblacional mostraron un alto grado de diversidad a nivel de individuos (Ht = 0.1933, Hw = 0.1872) y baja diferenciación entre poblaciones (Hb = 0.0061). Los resultados sugieren una alta tasa de migración que influye directamente en el grado de mezcla genética de los materiales analizados. El bajo índice de estructura poblacional apunta a un alto flujo genético entre las poblaciones, por lo que la especie no presenta mayor riesgo ante la deriva genética, minimizándose el riesgo de pérdida de alelos por fijación. Se sugiere el resguardado del recurso fitogénetico total y no únicamente de materiales promisorios, evitando así el riesgo de erosión genética de la especie y garantizando la permanencia de la diversidad genética, la cual será la base de futuros programas de mejoramiento.

Avocado is one of the most widely consumed crops worldwide and according to new theories, the Sierra Nevada region in California is suggested as the center of origin and Guatemala as one of the main domestication cen-ters. Through morphological characterizations, a high genetic diversity has been reported in the country, but due to the behavior of cross pollination and interracial hybridizations, it has not been possible to detail the current genetic status of the species. Molecular markers are useful for this type of study by focusing on differences at DNA level. This study analyzed the genetic diversity of the native Guatemalan avocado from seven geographic populations with AFLP molecular marker. Population structure data showed a high degree of diversity at the individual level (Ht = 0.1933, Hw = 0.1872) and low differentiation between populations (Hb = 0.0061). The results suggest a high rate of migration that directly influences the degree of genetic mixing of the analyzed materials. The low index of population structure points to a high genetic flow between populations, so that the species does not present a greater risk due to genetic drift, minimizing the risk of loss of alleles due to fixation. The protection of the total genetic resource is suggested, and not only of promising materials, thus avoiding the risk of genetic erosion of the species and guaranteeing the permanence of genetic diversity, which will be the basis of future breeding programs.

Retrospective analysis of second-line chemotherapy outcomes with paclitaxel or docetaxel in correlation with STMN1 polymorphism in advanced non-small cell lung cancer patients

Purpose. Second-line chemotherapy of advanced non-small cell lung cancer (NSCLC) with docetaxel or pemetrexed allows to achieve objective response rate only in 5-10 % of patients. Recent studies have shown that single nucleotide polymorphisms (SNPs) in genes encoding proteins which regulate dynamics of microtubules may be considered as predictive factors of response to taxane-based chemotherapy. STMN1 gene encodes stathmin 1, which plays role in cell division by regulation of microtubules epolarisation, and this process may be associated with taxanes’ effectiveness. Materials and methods. Using HRM-PCR technique, we evaluated the −2166C>T SNP of STMN1 gene in DNA from peripheral blood leucocytes of 54 advanced NSCLC patients treated in second-line monotherapy with docetaxel or paclitaxel. Results. Patients with TT genotype of STMN1 gene demonstrated significantly longer progression-free survival (PFS) and the lower risk of early disease progression after second-line treatment compared to patients with other STMN1 genotypes (median PFS: 7 and 2 months; p = 0.0154; HR = 0.371; 95 % CI 0.184-0.743). Early disease progression during second-line chemotherapy was significantly more frequently observed in patients with CC genotype of STMN1 in contrast to patients with presence of T allele (median PFS: 2 and 4 months; p = 0.0385; HR = 1.776; 95 % CI 0.905-3.445). Conclusion. Only selected NSCLC patients could benefit from second-line chemotherapy. Therefore, investigations of novel predictive molecular factors for proper qualification of patients to second-line taxane-based chemotherapy are justified. Studied SNP of STMN1 gene may have potential predictive role in such therapy (AU)

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Association between CC motif chemokine ligand 5 (CCL5) polymorphisms and asthma risk: an updated meta-analysis

Background: Findings regarding the associations between the CC motif chemokine ligand 5 (CCL5) -403G/A and -28C/G polymorphisms and asthma risk are controversial. We performed a meta-analysis to determine whether CCL5 polymorphisms are associated with asthma risk. Methods: We searched the Pubmed, Embase, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases for studies published before June 2013. The strength of associations was calculated using ORs with 95% CIs. Results: Twenty case-control studies were included in this meta-analysis. We did not observe a significant association between the CCL5 -403G/A polymorphism and asthma risk (OR, 1.10; 95% CI, 0.93-1.30; P=.25). The CCL5 -28C/G polymorphism, however, was associated with a significantly elevated asthma risk (OR, 1.17; 95% CI, 1.02-1.33; P=.02). Subgroup analyses found that the CCL5 -28C/G polymorphism was significantly associated with asthma risk in Asians (OR, 1.16; 95% CI, 1.01-1.33; P=.04) and children (OR, 1.29; 95% CI, 1.03-1.63; P=.03). Conclusions: This meta-analysis suggests that the CCL5 -28C/G polymorphism is a risk factor for asthma (AU)

Introducción: Existen discrepancias entre la asociación del riesgo de padecer asma y diferentes polimorfismos del ligando de la quimiocina CC5 (CCL5). En este trabajo se ha realizado un meta-análisis para determinar si los polimorfismos CCL5-403G / A y CCL5-28C / G se asocian con el riesgo de asma bronquial. Métodos: Se utilizaron diversas bases de datos para realizar las búsquedas de estudios publicados antes de junio de 2013, incluyendo: PubMed, EMBASE, CNKI (Infraestructura del Conocimiento Nacional Chino) y Wanfang Se calcularon los odd ratios combinados (OR) con intervalos de confianza del 95% (IC). Resultados: Se incluyeron un total de 20 estudios de casos y controles. No se encontró una asociación significativa entre el polimorfismo CCL5-403G / A y el riesgo de asma (OR = 1,10, IC del 95%: 0,93 a 1,30, p = 0,25). Por el contrario, el polimorfismo CCL5-28C / G, se asoció con un riesgo significativamente elevado de asma (OR = 1,17, IC del 95%: 1,02 a 1,33, p = 0,02). En los análisis de subgrupos, el riesgo de asma fue significativamente mayor en los asiáticos con el polimorfismo CCL5-28C / G (OR = 1.16, 95% IC 1,01-1,33, P = 0,04) y los niños (OR = 1.29, 95% IC 1,03-1,63, P = 0,03). Conclusiones: Este meta-análisis sugiere que el polimorfismo CCL5-28C / G es un factor de riesgo significativo para padecer asma bronquial (AU)