Abstract To know the genetic situation of the Pampa Rocha, Celta, Bizaro Portuguese, Duroc, Iberian Extremeño and Iberian Andalusian porcine populations, their genetic structure and population dynamics were studied on the IGF2 and MC4R genes, which determine meat characteristics and quality. The degree of genetic variability (He = 0.2511 in Pampa Rocha; 0.0278 in Celta; 0,1453 in Bizaro Portuguese; 0.3719 in Duroc; 0.0764 in Iberian Extremeño and 0.0384 in Iberian Andalusian), genetic distance, and the presence or absence of consanguinity were studied. The Fis values were positive for the Duroc population (0.00426) indicating a very low inbreeding, the rest of the populations did not present consanguinity. Significant deviations (P ≤ 0.05) in the Hardy-Weinberg (HW) equilibrium were obtained for the IGF2 locus in Celta, Iberian Extremeño, and Iberian Andalusian populations with the G allele fixed, while the Bizaro Portuguese, Pampa Rocha, and Duroc populations presented polymorphism, the G allelic frequency was much higher than A allele, except in the Duroc breed (0.15). These findings could help breeders to increase the presence of the A allele for the improvement of muscle mass and reduction in the back-fat thickness in this breed. All the studied populations presented polymorphism for the MC4R locus with different frequencies for each allele. Furthermore, these results could allow developing strategies against anthropogenic activities that hinder the conservation of the biodiversity of these porcine breeds.

Resumen La abiotrofia cerebelar (AC) es una enfermedad neurodegenerativa causada por una mutación en el ADN que afecta a las células de Purkinje del cerebelo, produciendo principalmente problemas en el balance y la coordinación de los animales. Entre las especies que se ven afectadas se encuentra la equina, particularmente la raza Árabe. En este trabajo se presenta el caso de un potrillo árabe que presentó sintomatología compatible con AC. Los hallazgos clínicos se confirmaron mediante estudios moleculares y confirmación por histopatología de las lesiones. Los estudios moleculares permitieron confirmar la presencia de la mutación causal. Dados estos hallazgos y que la sintomatología neurológica compatible con la abiotrofia cerebelar en equinos no es nueva en nuestro país, se considera que sería importante estudiar a nivel poblacional la raza Árabe, con el fin de conocer la prevalencia y casuística de AC en Uruguay.

Summary Cerebellar abiotrophy (CA) is a neurodegenerative disease caused by a mutation in the DNA that affects the Purkinje cells of the cerebellum, mainly causing problems in the balance and coordination of animals. Among the species that are affected is equine, mainly the Arabian breed. In this study we presented the case of an Arabian foal with clinic signs compatible with the pathology mentioned before. Histopathological and molecular studies were carried out to confirm the clinical findings, giving results that were positive for CA in both cases. Considering these findings and that the neurological symptomatology compatible with CA in horses is not new in our country, it is important to study the Arabian breed at a population level, in order to know the prevalence of CA in Uruguay.

Various genetic markers, including microsatellites, have been used to analyze the genetic polymorphism and heterozygosity in canine breeds. In this work, we used nine microsatellite markers to investigate the genetic variability in Cimarron Uruguayo dogs, the only officially recognized native canine breed in Uruguay. DNA from 30 Cimarron Uruguayo dogs from northeastern and southern Uruguay was analyzed. The allelic frequencies for each micro-satellite, the genetic variability and the consanguinity were calculated, as were the polymorphic information content (PIC) and the probability of exclusion (PE). All of the microsatellites studied were polymorphic. FH 2361, FH 2305 and PEZ 03 were the most informative, with PIC values > 0.7, in agreement with results for other canine breeds. The PE values for the markers were within the ranges previously described and were generally greater for microsatellites with higher PIC values. The heterozygosity value (0.649) was considered high since only nine microsatellites were analyzed. Compared with data for other breeds, the results obtained here indicate that Cimarron Uruguayo dogs have high genetic diversity.

La azacitidina (5-azaC) es una sustancia que actúa inhibiendo la metilación del ADN, es utilizada en experiencias de clonación, transgénesis por transferencia nuclear y estudios de fragilidad cromosómica. Se ha observado la manifestación de diversas patologías en animales domésticos nacidos de experiencias de clonación. Ellas estarían asociadas a una inexacta reprogramación nuclear relacionada con fenómenos epigenéticos de metilación del ADN. En el presente trabajo se realizó una curva de inducción con diferentes concentraciones finales de 5-azaC (0 uM, 5 uM, 10 uM, 20 uM, 50 uM y 70 uM) con el objetivo de estudiar los efectos sobre la estructura cromosómica en cultivos linfocitarios bovinos. Se utilizó la técnica de macrocultivo para análisis cromosómico a partir de sangre de un bovino macho (Bos taurus, Holstein Friesian). Se analizó un total de 50 placas metafásicas por tubo de cultivo y se encontraron diferencias significativas (p<0.01) en cuanto a las fracturas del cromosoma X en el cultivo control frente al cultivo con mayor concentración de 5-azaC. El cromosoma Y no presentó fracturas. En los cultivos con concentraciones de 50 uM y 70 uM se observó descondensación cromosómica (12% y 16%) y fracturas centroméricas en autosomas (2% y 4%).

Azacytidine (5-azaC) is a substance that inhibits the metilation of DNA, being used in cloning experiments, nuclear transference transgenesis and in chromosomal fragility studies. The manifestation of diverse pathologies has been observed in domestic animals born from cloning experiments. These would be associated to an incorrect nuclear reprogramation related to epigenetic metilation phenomena of the DNA. In the present work an induction curve with different final concentrations of 5-azaC (0 uM, 5 uM, 10 uM, 20 uM, 50 uM and 70 uM) were carried out, with the objective of studying the effects on chromosome structure in bovine lymphocyte cultures. The macroculture technique was used for chromosomic analysis, from a blood sample of a male bovine (Bos taurus, Holstein Friesian). A total of 50 metaphases were analyzed from each culture. Significative differences (p<0.01) were found regarding the break points of chromosome X in the control culture with respect to the culture with higher concentration of 5-azaC. Chromosome Y did not show break points. The cultures with higher concentration of 5-azaC (50 uM and 70 uM) presented chromosomic decondensation (12% and 16%) and autosomic centromeric break points (2% and 4%).