ARTICLE 1 - opinion

GENETIC DIVERSITY AND GENETIC VARIABILITY: TWO DIFFERENT CONCEPTS ASSOCIATED TO PLANT GERMPLASM AND BREEDING

LA DIVERSIDAD GENÉTICA Y LA VARIABILIDAD GENÉTICA: DOS CONCEPTOS DIFERENTES ASOCIADOS AL GERMOPLASMA Y AL MEJORAMIENTO GENÉTICO VEGETAL

Pedro Rimieri

This paper differentiates plant genetic resources maintained in situ and ex situ for protection and conservation, from those resources that man collects, maintains and uses for his subsistence by developing cultivated varieties through any artificial selection method. The imprecision, confusion and distortion found in many papers related to the issue raised here with respect to terminology, its meaning, its scope and its consequences, motivated the development of this opinion work. In plant breeding working collections are used as a source of variability and adaptation. In this process, unfailingly, only a part of the genetic variability is used, which is restricted in each selective cycle since the purpose of this process is to obtain new cultivars. In the selection process there is always a loss of genetic variability with respect to the population that gave rise to it. The confusion mentioned with respect to the loss of genetic variability resides in the following: the greater probabilities of success in a plant breeding program will be associated to the availability of a wide genetic variability in the starting elite collection and not in the obtained cultivar. One of the reiterated concepts attributes the loss of genetic variability to the advent of new cultivars and the narrow genetic base that they represent. The loss of genetic variability is a consequence of the achievement of genetic progress in plant breeding. In this context, the respect for diversity in protected areas and agrobiodiversity in agricultural areas, is the way for producing profitable yields while maintaining the long-term productivity as a result of the implementation of plant breeding.

Key words: genetic variability, genetic diversity, plant breeding, plant genetic resources
Language: Spanish

ARTÍCLE 2 - research

HEP-2 CELL LINE AS AN EXPERIMENTAL MODEL TO EVALUATE GENOTOXIC EFFECTS OF PENTAVALENT INORGANIC ARSENIC

HEP-2 COMO MODELO EXPERIMENTAL PARA EVALUAR LOS EFECTOS GENOTÓXICOS DEL ARSÉNICO INORGÁNICO PENTAVALENTE

Andrioli N.B., Chaufan G., Coalova I., Ríos de Molina M.C., Mudry M.D.

Early detection of toxic events induced by xenobiotics is necessary for a proper assessment of human risk after the exposure to those agents. The aim of this work was to evaluate the cell line HEp-2 as an experimental model to determine the genotoxic effects of sodium arsenate. To this end, we determined the metabolic activity cells by the MTT test on seven concentrations of arsenate that range from 27 to 135,000 µM, obtaining the median lethal concentration (LC₅₀), the lowest observed effect concentration (LOEC), and the not observed effect concentration (NOEC) of sodium arsenate at 24 h of exposition. According to the cytotoxic response obtained, we evaluated the genotoxic effect of the 27 and 270 µM concentrations by using the micronucleus assay and chromosomal aberrations test. We found a statistically significant increase (p<0.05) in the frequency of micronuclei between control cultures and those exposed to the highest concentration of sodium arsenate. Furthermore, the frequencies of nucleoplasmic bridges and tripolar mitosis were significantly higher in cell cultures exposed to the above concentrations compared to the control cultures (p<0.05). The participation of the glutathione system as response to the arsenate exposition was also analyzed, and a statistically significant increase in the glutathione content was found in those cells exposed to 27 µM of arsenate. The Glutathione S-transferase activity did not increase in the exposed cells compared to control cells, suggesting that the arsenate reduction involved other metabolic pathways in the HEp-2 cells. These results confirm that, under the conditions carried out in this study, sodium arsenate is genotoxic for HEp-2 cells. Therefore, we suggest that this cell line would be a good model for the assessment of the cytotoxic and genotoxic effects of xenobiotics on human cells.

Key words: cytotoxicity, genotoxicity, Glutathione, HEp-2 cell line
Language: English

ARTÍCLE 3 - research

A RAPID, NON INVASIVE AND SIMPLE MOLECULAR METHOD FOR SEX DETERMINATION IN PYGOSCELIS PENGUINS

UN MÉTODO MOLECULAR RÁPIDO, NO INVASIVO Y SIMPLE PARA DETERMINAR EL SEXO EN PINGÜINOS PIGOSCÉLIDOS

Santos M.R., Santos M.M., Terán E.M., Bailliet G., Juáres M.A.

In Adélie penguins (Pygoscelis adeliae) and gentoo penguins (Pygoscelis papua), the conspicuous sexual dimorphism often makes it difficult to determine sex on the basis of external morphology. The information about sex is important in many  ecology and conservation studies. In this paper we evaluated the use of an established primer pair (2550F/2718R) to identify sex in sexually monomorphic birds. In both penguin species, it resulted in two distinct CHD1Z and CHD1W PCR bands, allowing sex identification. This is a simple, rapid and cheap system for molecular sexing of gentoo and Adélie penguins.

Key words: CHD gene, sex identification, penguins
Language: Spanish

ARTÍCLE 4 - research

MIGRATIONS, ADMIXTURE AND GENETIC DIVERSITY IN CENTRAL ARGENTINIAN PATAGONIA: ANALYSIS OF AUTOSOMAL ALU POLYMORPHISMS

MIGRACIONES, MESTIZAJE Y DIVERSIDAD GENÉTICA EN LA PATAGONIA CENTRAL ARGENTINA: ANÁLISIS DE POLIMORFISMOS AUTOSÓMICOS ALU

Parolin M.L., Zanetti D., Calò C.M., Esteban E., Avena S., Carnese F.R., Moral P.

This study aimed to analyze autosomal Alu insertions in three localities from Patagonia Argentina belonging to the Andes region and the coast of the Chubut province. Knowledge of the genetic diversity of these populations, along with the genealogical data, will contribute to better understand historical information, differential migration process and bio-demographic composition of the Central Patagonia region. In order to achieve this objective, 16 autosomal Alu insertion polymorphisms were genotyped: ACE, APO-A1, TPA25, FXIIIB, A25, HS4.32, D1, HS4.69, HS2.43, Sb19.12, Yb8NBC120, Sb19.3, Yb8NBC125, Ya5NBC221, DM, and CD4. Our results showed that the Central Patagonia region presents a complex continental genetic admixture with marked Native American roots (39% ± 1.2), Eurasian (56% ± 1.73) and, to a lesser extent, African (5% ± 1.7). The genetic proximity of the Patagonian samples in relation to groups from Europe and Northern Africa, but with a displacement towards the native communities, constitutes a clear indicator of the  differential admixture process that took place in different regions of Argentina. Moreover, genetic differences were observed between Patagonian localities and Bahía Blanca (Central region of Argentina). These observations warned us that population genetic constitution analysis cannot be approached without bearing in mind the regional particularities, which are the result of the different historical, migratory, social-economic and demographic processes that occurs in the country.

Key words: Alu insertion polymorphisms, Argentina Central Patagonia, Admixture, Migrations
Language: English

ARTÍCLE 5 - review article

GENETIC CHARACTERIZATION OF FOUR POPULATIONS OF ARGENTINIAN CREOLE SHEEP

CARACTERIZACIÓN GENÉTICA DE CUATRO POBLACIONES DE OVINOS CRIOLLOS DE ARGENTINA

Peña S., Martínez A., Villegas Castagnasso E., Aulicino M., Género E.R., Giovambattista G., Martínez R.D.

Creole sheep are the founders of sheep farming in Argentina and have contributed in a sustained way to the economic, social and cultural development of some regions of this country. However, it is a scarcely valorised and poorly studied genetic resource. In order to genetically characterize the Argentinian Creole sheep, DNA samples were taken from four representative populations located in the provinces of Buenos Aires, Corrientes, Santiago del Estero and Salta. These flocks were selected because they are considered to be conserved groups, they have the phenotypic characteristics of the creole breed and there are no records about the introduction of animals of other breeds into those systems. A total of 30 microsatellites and the D-loop region of mitochondrial DNA were analysed. Microsatellite analysis showed high level of genetic diversity within populations (Ho= 0.676; He= 0.685; PIC= 0.713). This variability is explained by differences between molecular patterns of the studied individuals, which can be classified into three  significantly different population groups: BA, SA, SE+CO. Since these populations explain very little of the total variability (7.6%), it can be considered that they belong to a same race. The analysis of the mitochondrial D-loop showed that Argentinian Creole sheep have haplotypes belonging to the Asian haplogroup, which is widely distributed in the Spanish breeds, which are considered to be their ancestors. The results obtained in the present study will provide information to develop management criteria for this genetic resource in Argentina, in order to implement their conservation, recovery and/or to develop breeding programs.

Key words: Sheep, genetic variability, microsatellites, mitochondrial DNA
Language: Spanish

Obituary

DR. EDUARDO ALBERTO MOSCONE