Genetic characterization of Argentine and Bolivian Creole cattle breeds assessed through microsatellites

In the present report, the polymorphisms from 9 microsatellites were used to assess genetic diversity and relationships in 4 Creole cattle breeds from Argentina and Bolivia, 4 European taurine breeds, and 2 American zebu populations. The Creole populations display a relatively high level of genetic variation as estimated by allelic diversity and heterozygosity, whereas the British breeds displayed reduced levels of genetic diversity. The analysis of molecular variance indicated that 7.8% of variance can be explained by differences among taurine and zebu breeds. Consistent with these results, the first principal component (PC), which comprised the 40% of the total variance, clearly distinguishes these 2 groups. In addition, all constructed phylogenetic trees cluster together Nelore and Brahman breeds with robust bootstrap values. Only 1% of variance was due to difference between American Creole and European taurine cattle. Although this secondary split was supported by the classical genetic distance and the second PC (15%), the topology of trees is not particularly robust. The presence of zebu-specific alleles in Creole cattle allowed estimating a moderate degree of zebu admixture. When these data were compared with mitochondrial and Y chromosomal studies, a clearl pattern of male-mediated introgression was revealed. The results presented here contribute to the understanding of origin and history of the American Creole cattle.Instituto de Genética Veterinari

In vitro approach to the study of chronic exposure to low doses of x-rays

El presente trabajo fue realizado con el fin de estudiar el efecto de dosis bajas y repetidas de radiación sobre dos líneas celulares de la misma especie. Se desarrolló un modelo in vitro para evitar la influencia de los factores de confusión que afectan a los estudios epidemiológicos y para simular una exposición crónica. Las técnicas utilizadas fueron el ensayo cometa y el análisis de apoptosis temprana; estas se llevaron a cabo inmediatamente después de la exposición y luego de la irradiación crónica. La irradiación secuencial indujo un aumento de células con daño en el ADN. El índice de daño fue mayor que el de los controles en ambas líneas celulares, tanto inmediatamente después de la exposición como luego de la irradiación crónica. Este aumento fue estadísticamente significativo solamente para la línea celular transformada luego de la irradiación crónica (p<0,001). El análisis de apoptosis arrojó niveles significativamente mayores al control para ambas líneas celulares luego de la exposición crónica (p<0.001). Se demostró que la exposición crónica a radiación ionizante de dosis bajas indujo daño en el ADN y apoptosis en células de hámster chino cultivadas in vitro. Las respuestas de ambos tipos celulares fueron algo diferentes. Evidentemente, el tipo celular debe ser tenido en cuenta a la hora de diseñar experimentos in vitro para entender los efectos de la radiación crónica de dosis baja en las poblaciones celulares.The present research was undertaken in order to study the effect of repeated low doses of radiation on two different cell lines from the same species. An in vitro model test was developed to avoid the influence of the confounding factors affecting epidemiological studies and to simulate a chronic exposure (50 mSv of x-rays during ten consecutive days). Comet assay and early apoptosis were analyzed immediately after exposure and after chronic irradiation. Sequential irradiation induced an increase of cells showing DNA damage. Index Damage was higher than that of the controls in both cell lines immediately after exposure and after chronic irradiation; these differences between exposed and control cells were statistically significant only for the transformed cell line after chronic irradiation (p<0.001). Significantly higher levels of apoptosis were scored after chronic exposure in both cells lines (p<0.001). The induction of DNA damage and apoptosis in hamster cells by chronic exposure to low dose ionizing radiation was demonstrated. Cell types reacted differently to chronic exposure; though further investigation is needed to understand the mechanisms of radiation effects on chronic low-dose-exposed cell populations, cellular type should be taken into account in the design of in vitro experiments to understand low-dose-irradiation effects.Instituto de Genética Veterinari

In vitro approach to the study of chronic exposure to low doses of x-rays

El presente trabajo fue realizado con el fin de estudiar el efecto de dosis bajas y repetidas de radiación sobre dos líneas celulares de la misma especie. Se desarrolló un modelo in vitro para evitar la influencia de los factores de confusión que afectan a los estudios epidemiológicos y para simular una exposición crónica. Las técnicas utilizadas fueron el ensayo cometa y el análisis de apoptosis temprana; estas se llevaron a cabo inmediatamente después de la exposición y luego de la irradiación crónica. La irradiación secuencial indujo un aumento de células con daño en el ADN. El índice de daño fue mayor que el de los controles en ambas líneas celulares, tanto inmediatamente después de la exposición como luego de la irradiación crónica. Este aumento fue estadísticamente significativo solamente para la línea celular transformada luego de la irradiación crónica (p<0,001). El análisis de apoptosis arrojó niveles significativamente mayores al control para ambas líneas celulares luego de la exposición crónica (p<0.001). Se demostró que la exposición crónica a radiación ionizante de dosis bajas indujo daño en el ADN y apoptosis en células de hámster chino cultivadas in vitro. Las respuestas de ambos tipos celulares fueron algo diferentes. Evidentemente, el tipo celular debe ser tenido en cuenta a la hora de diseñar experimentos in vitro para entender los efectos de la radiación crónica de dosis baja en las poblaciones celulares.The present research was undertaken in order to study the effect of repeated low doses of radiation on two different cell lines from the same species. An in vitro model test was developed to avoid the influence of the confounding factors affecting epidemiological studies and to simulate a chronic exposure (50 mSv of x-rays during ten consecutive days). Comet assay and early apoptosis were analyzed immediately after exposure and after chronic irradiation. Sequential irradiation induced an increase of cells showing DNA damage. Index Damage was higher than that of the controls in both cell lines immediately after exposure and after chronic irradiation; these differences between exposed and control cells were statistically significant only for the transformed cell line after chronic irradiation (p<0.001). Significantly higher levels of apoptosis were scored after chronic exposure in both cells lines (p<0.001). The induction of DNA damage and apoptosis in hamster cells by chronic exposure to low dose ionizing radiation was demonstrated. Cell types reacted differently to chronic exposure; though further investigation is needed to understand the mechanisms of radiation effects on chronic low-dose-exposed cell populations, cellular type should be taken into account in the design of in vitro experiments to understand low-dose-irradiation effects.Instituto de Genética Veterinari

Mitochondrial variability in the D-loop of four equine breeds shown by PCR-SSCP analysis

A fragment of 466 base pairs from a highly variable peripheral region of the mitochondrial D-loop of horses was amplified and analyzed by single stranded conformational polymorphism (SSCP). Fourteen distinct SSCP variants were detected in 100 horses belonging to four breeds (Arabian, ARB; Thoroughbred, TB; Argentinian Creole, ARC; and Peruvian Paso from Argentina, PPA). Each breed showed four to eight SSCP variants, many of which were shared between two or three of the studied breeds. Arabian horses were the most variable (eight variants), with three variants unique to the breed. PPA and ARC showed two and one characteristic SSCP variants, respectively, while TB shared all its variants with at least one of the other breeds. An analysis based on the presence/absence of the variants revealed a closer relationship between PPA and TB, which was not completely unexpected considering the mixed ancestry of the PPA mares. The results also confirm the efficiency of SSCP to detect variability in horse mitochondrial DNA.Instituto de Genética Veterinari

Prediction of non-genotoxic carcinogenicity based on genetic profiles of short term exposure assays

Non-genotoxic carcinogens are substances that induce tumorigenesis by non-mutagenic mechanisms and long term rodent bioassays are required to identify them. Recent studies have shown that transcription profiling can be applied to develop early identifiers for long term phenotypes. In this study, we used rat liver expression profiles from the NTP (National Toxicology Program, Research Triangle Park, USA) DrugMatrix Database to construct a gene classifier that can distinguish between non-genotoxic carcinogens and other chemicals. The model was based on short term exposure assays (3 days) and the training was limited to oxidative stressors, peroxisome proliferators and hormone modulators. Validation of the predictor was performed on independent toxicogenomic data (TG-GATEs, Toxicogenomics Project-Genomics Assisted Toxicity Evaluation System, Osaka, Japan). To build our model we performed Random Forests together with a recursive elimination algorithm (VarSelRF). Gene set enrichment analysis was employed for functional interpretation. A total of 770 microarrays comprising 96 different compounds were analyzed and a predictor of 54 genes was built. Prediction accuracy was 0.85 in the training set, 0.87 in the test set and increased with increasing concentration in the validation set: 0.6 at low dose, 0.7 at medium doses and 0.81 at high doses. Pathway analysis revealed gene prominence of cellular respiration, energy production and lipoprotein metabolism. The biggest target of toxicogenomics is accurately predict the toxicity of unknown drugs. In this analysis, we presented a classifier that can predict non-genotoxic carcinogenicity by using short term exposure assays. In this approach, dose level is critical when evaluating chemicals at early time points.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari

Genetic characterization of Argentine and Bolivian Creole cattle breeds assessed through microsatellites

In the present report, the polymorphisms from 9 microsatellites were used to assess genetic diversity and relationships in 4 Creole cattle breeds from Argentina and Bolivia, 4 European taurine breeds, and 2 American zebu populations. The Creole populations display a relatively high level of genetic variation as estimated by allelic diversity and heterozygosity, whereas the British breeds displayed reduced levels of genetic diversity. The analysis of molecular variance indicated that 7.8% of variance can be explained by differences among taurine and zebu breeds. Consistent with these results, the first principal component (PC), which comprised the 40% of the total variance, clearly distinguishes these 2 groups. In addition, all constructed phylogenetic trees cluster together Nelore and Brahman breeds with robust bootstrap values. Only 1% of variance was due to difference between American Creole and European taurine cattle. Although this secondary split was supported by the classical genetic distance and the second PC (15%), the topology of trees is not particularly robust. The presence of zebu-specific alleles in Creole cattle allowed estimating a moderate degree of zebu admixture. When these data were compared with mitochondrial and Y chromosomal studies, a clearl pattern of male-mediated introgression was revealed. The results presented here contribute to the understanding of origin and history of the American Creole cattle.Instituto de Genética Veterinari

Genética forense no-humana

El presente libro nace como producto de una convocatoria para Libros de Cátedra de la Universidad Nacional de la Plata. La propuesta, avalada por la Facultad de Ciencias Veterinarias, permitirá introducir al lector en los principales aspectos de la identificación genética de animales y/o sus productos derivados, conocer los principales métodos de genotipificación utilizados en genética forense, reconocer los lineamientos de estandarización y acreditación de los laboratorios de genética forense y por ultimo fortalecer las capacidades de los futuros profesionales en el área de genética. Entre los autores de esta obra se destacan profesionales de distintas entidades académicas: Universidades Nacionales (UNCPBA, UNLP), del exterior (Universidade Federal de Minas Gerais. Belo Horizonte, Brasil; Universidad de Western Cape Sudáfrica), laboratorios de servicios nacionales (Laboratorio de ADN, Facultad de Ciencias Veterinarias, UNCPBA, Tandil, de la CICPBA y el CONICET); internacionales (Laboratório de Genética, Escola de Veterinária y el Myleus Biotechnology Research Team, Belo Horizonte, Brasil) y profesionales del Cuerpo de Instructores de la Fiscalía General del Departamento Judicial Azul y de Junín de la Provincia de Buenos Aires. Los coordinadores del presente libro son profesionales responsables del dictado en la carrera de grado de Médico Veterinario de la UNLP, de un curso optativo de Genética Veterinaria Forense de la UNLP, y miembros del Servicio Externo de Diagnóstico Genético en Animales Domésticos del Instituto de Genética Veterinaria (IGEVET, UNLP-CONICET).Facultad de Ciencias Veterinaria

Mitochondrial variability in the D-loop of four equine breeds shown by PCR-SSCP analysis

A fragment of 466 base pairs from a highly variable peripheral region of the mitochondrial D-loop of horses was amplified and analyzed by single stranded conformational polymorphism (SSCP). Fourteen distinct SSCP variants were detected in 100 horses belonging to four breeds (Arabian, ARB; Thoroughbred, TB; Argentinian Creole, ARC; and Peruvian Paso from Argentina, PPA). Each breed showed four to eight SSCP variants, many of which were shared between two or three of the studied breeds. Arabian horses were the most variable (eight variants), with three variants unique to the breed. PPA and ARC showed two and one characteristic SSCP variants, respectively, while TB shared all its variants with at least one of the other breeds. An analysis based on the presence/absence of the variants revealed a closer relationship between PPA and TB, which was not completely unexpected considering the mixed ancestry of the PPA mares. The results also confirm the efficiency of SSCP to detect variability in horse mitochondrial DNA.Instituto de Genética Veterinari

Analysis of genetic diversity and population structure in Argentine and Bolivian Creole cattle using five loci related to milk production

Data from five protein-coding loci related to dairy production were used to study the genetic diversity and population structure of Argentine and Bolivian Creole cattle breeds. Genomic DNA was extracted from blood samples of six Creole cattle breeds: Argentine (n = 230), Patagonian (n = 25); "Saavedreño" (n = 140), "Chaqueño Boliviano" (n = 30), "Yacumeño" (n = 27), and "Chusco" (n = 11). κ-casein, β-lactoglobulin, growth hormone and prolactin were measured by PCR-RFLP, while αS1-casein was typed by PCR-ASO. The results are discussed, focusing on: historical origin, recent differentiation and selection events, Zebu gene introgression, and population structure. This work shows that: (i) For the studied genes, the observed gene frequency profiles of Argentine and Bolivian Creole cattle breeds were close to the data reported for Iberian breeds and for other South-American Creole cattle breeds which are historically related; (ii) although Zebu gene introgression has been reported at the studied loci, these breeds seem to be far from the Zebu gene frequency profiles; and (iii) the Argentine and Bolivian Creole cattle showed significant levels of subdivision, but each population has maintained its degree of genetic variability.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari

Genetic markers for susceptibility and resistance to infectious diseases in farm animals. Major histocompatibility complex (MHC) loci as candidate genes

Las enfermedades infecciosas en animales domésticos aún permanecen como una de las principales causas de morbilidad y mortalidad, con las consecuentes pérdidas productivas, siendo uno de los principales problemas sanitarios en los países en desarrollo. El resultado de la infección puede estar influenciado por factores ambientales, variables propias del patógeno y factores del hospedador. En consecuencia se han realizado numerosas investigaciones dirigidas a establecer las relaciones entre la probabilidad de adquirir o desarrollar la enfermedad y la constitución genética de los individuos. Los loci del Complejo Principal de Histocompatibilidad son considerados genes candidatos dado el rol que desempeñan en la respuesta inmune. En este trabajo de revisión se describen las principales estrategias implementadas para detectar el componente genético de la susceptibilidad/resistencia y se detallan las consideraciones generales para la elección del método adecuado. Además, se describen y discuten los principales resultados obtenidos en las diferentes especies de animales domésticos: equinos (sarcoiditis, hipersensibilidad dérmica a insectos), bovinos (leucosis, mastitis, dermatofilosis), caninos (leishmaniasis) y aves de corral (enfermedad de Marek). Finalmente, se hace una breve mención de estudios de asociación realizados con otros genes candidatos que no pertenecen al MHC y se discute la situación actual y las perspectivas futuras de esta área del conocimiento.Infectious diseases in farm animals are the main cause of morbidity and mortality and because of the consequent productive losses is considered one of the major sanitary problems in developing countries. The outcome of infection can be divided into environment, pathogen and host factors. Several investigations have intended to relate the probability of acquire or develop a disease and the genetic constitution of the individuals. Major Histocompatibility Complex loci are proposed as candidate genes due to their role on the immune system. In this review the principal strategies to detect the genetic component of susceptibility/resistance are described and the general norms to select the accurate method are detailed. Moreover, the main results obtained in different farm animals: equine (sarcoids, insect dermal hipersensibility), bovine (leukosis, mastitis, dermatophilosis), canine (leishmaniasis) and poultry (Marek´s disease) are presented. Finally, a brief description of association studies with other candidate non-MHC genes is mentioned, and the present status and future perspectives are discussed.Facultad de Ciencias Veterinaria