Caracterización de polimorfismos en los genes PPARG, CEBPA, LIPE, RXRA y FABP4 asociados a metabolismo lipídico en razas de ganado bovino

La calidad de la carne está determinada por cualidades como el marmoleo, el sabor, la terneza y la composición, entre otras. Estas cualidades están reguladas a distintos niveles, y uno de ellos es la genética. Hoy en día se conoce buena parte de las vías metabólicas que regulan estas características, y se han propuesto "genes candidatos" que codifican factores importantes dentro de estas vías. Los genes PPARG, CEBPA, FABP4, LIPE y RXRA son parte de las vías de diferenciación adipocítica y del metabolismo lipídico. El objetivo de este proyecto fue caracterizar la variabilidad genética en estos genes en razas bovinas con diferente calidad carnicera. Los datos se obtuvieron por medio de técnicas moleculares (reacción en cadena de la polimerasa, re-secuenciación) aplicadas a muestras de ADN extraídas de animales pertenecientes a diferentes razas criadas alrededor del mundo. Luego se realizaron una serie de análisis a través de programas bioinformáticos y herramientas web. Algunos de los polimorfismos detectados en los genes y otros disponibles en las bases de datos de internet fueron seleccionados para realizar estudios de validación a nivel poblacional y análisis estadísticos de asociación a caracteres de calidad carnicera en una población de ganado local. Los resultados fueron diversos: PPARG y CEBPA presentaron una variabilidad moderada, y FABP4 y LIPE presentaron una variabilidad alta. Algunos de los polimorfismos analizados sugieren una asociación a la composición lipídica de la carne y otros caracteres de engrasamiento, como espesor de grasa dorsal. Algunas de las posibles explicaciones biológicas para estas asociaciones fueron analizadas con diferentes herramientas bioinformáticas y se observaron algunos fenómenos interesantes. El conocimiento de la variabilidad existente en estos genes es de importancia para complementar los métodos de selección genética tradicionales y mejorar la calidad del ganado.Facultad de Ciencias Veterinaria

Creating chimeras: Embryonic stem cells incorporated

Gene modification within the murine genome has become a powerful and invaluable tool to investigate development. One example of the utility of such technology is providing a method by which researchers can follow cells throughout development via the introduced genetic modifications.Fil: Pascottini, Osvaldo Bogado. University of Chicago; Estados UnidosFil: Goszczynski, Daniel Estanislao. University of Chicago; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nguyen, Alexandra L.. University of Chicago; Estados Unido

Capturing chaotic chromosomes: Pairing in action

Accurate chromosome segregation is critical for the formation of haploid gametes, and therefore healthy offspring. Errors in segregation result in aneuploidy, which increases exponentially with maternal age (Hassold and Hunt, 2001). Maternally aged mouse oocytes were recently found to exhibit premature sister chromatid separation due to reduced levels of Securin, an essential regulator of sister chromatid cohesion (Nabti et al, 2017). This landmark finding was facilitated by using chromosome spreads that allow for the visualization of meiotic processes, such as recombination, synapsis, crossing over, and cohesion. This powerful technique is easy to perform and analyze, and allows for the identification of markers for different processes, including DNA damage and repair.Fil: Bertucci, Micka C.. University of Chicago; Estados UnidosFil: Das, Arunika. University of Chicago; Estados UnidosFil: Fitzgerald, Harriet C.. University of Chicago; Estados UnidosFil: Goszczynski, Daniel Estanislao. University of Chicago; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Assessing the association of single nucleotide polymorphisms in thyroglobulin gene with age of puberty in bulls

Puberty is a stage of sexual development determined by the interaction of many loci and environmental factors. Identification of genes contributing to genetic variation in this character can assist with selection for early pubertal bulls, improving genetic progress in livestock breeding. Thyroid hormones play an important role in sexual development and spermatogenic function. The objective of this study was to evaluate the association between single nucleotide polymorphisms (SNPs) located in thyroglobulin(TG) gene with age of puberty in Angus bulls. Four SNPs were genotyped in 273 animals using SEQUENOM technology and the association between markers and puberty age was analyzed. Results showed a significant association (P < 0.05) between these markers and puberty age estimated at a sperm concentration of 50 million and a progressive motility of 10%. This is the first report of an association of TG polymorphisms with age of puberty in bulls, and results suggest the importance of thyroidal regulation in bovine sexual development and arrival to puberty.Instituto de Genética Veterinari

Assessing the association of single nucleotide polymorphisms in thyroglobulin gene with age of puberty in bulls

Puberty is a stage of sexual development determined by the interaction of many loci and environmental factors. Identification of genes contributing to genetic variation in this character can assist with selection for early pubertal bulls, improving genetic progress in livestock breeding. Thyroid hormones play an important role in sexual development and spermatogenic function. The objective of this study was to evaluate the association between single nucleotide polymorphisms (SNPs) located in thyroglobulin(TG) gene with age of puberty in Angus bulls. Four SNPs were genotyped in 273 animals using SEQUENOM technology and the association between markers and puberty age was analyzed. Results showed a significant association (P < 0.05) between these markers and puberty age estimated at a sperm concentration of 50 million and a progressive motility of 10%. This is the first report of an association of TG polymorphisms with age of puberty in bulls, and results suggest the importance of thyroidal regulation in bovine sexual development and arrival to puberty.Fil: Fernandez, María Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Genética Veterinaria "ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Goszczynski, Daniel Estanislao. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Genética Veterinaria "ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Prando, Alberto José. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Peral Garcia, Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Genética Veterinaria "ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Baldo, Andrés. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Genética Veterinaria "ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Liron, Juan Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Genética Veterinaria "ingeniero Fernando Noel Dulout"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentin

Bases de datos en genética forense

En la práctica de genética forense de rutina, una vez que las muestras llegan al laboratorio, se realizan una serie de pasos sucesivos durante la resolución de casos forenses: extracción de ADN, tipificación de los marcadores genéticos, análisis de los resultados, estimación de los índices forenses y redacción de informes. Es por esta razón que los genetistas forenses, tanto dedicados a genética forense humana como no humana, deben recurrir a las bases de datos genéticos para estimar estadísticamente el valor de los resultados presentados en los informes forenses y, por lo tanto, determinar el peso de la evidencia en un juicio. Además, es frecuente que el perfil de ADN de una evidencia tenga que ser comparado con uno obtenido previamente, motivo por el cual ha surgido la necesidad de implementar las denominadas bases datos forenses, definidas como "el conjunto de programas informáticos (software) y soportes físicos (hardware) donde se almacena de modo ordenado y coherente la información de los perfiles genéticos, así como todo dato asociado a la muestra/individuo, información que luego puede ser recuperada y comparada de modo automático de acuerdo a parámetros previamente establecidos“.Fil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Goszczynski, Daniel Estanislao. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Fernandez, María Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Liron, Juan Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Peral Garcia, Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentin

Runs of homozygosity in a selected cattle population with extremely inbred bulls: Descriptive and functional analyses revealed highly variable patterns

The analysis of runs of homozygosity (ROH), using high throughput genomic data, has become a valuable and frequently used methodology to characterize the genomic and inbreeding variation of livestock and wildlife animal populations. However, this methodology has been scarcely used in highly inbred domestic animals. Here, we analyzed and characterized the occurrence of ROH fragments in highly inbred (HI; average pedigree-based inbreeding coefficient FPED = 0.164; 0.103 to 0.306) and outbred Retinta bulls (LI; average FPED = 0.008; 0 to 0.025). We studied the length of the fragments, their abundance, and genome distribution using high-density microarray data. The number of ROH was significantly higher in the HI group, especially for long fragments (>8Mb). In the LI group, the number of ROH continuously decreased with fragment length. Genome-wide distribution of ROH was highly variable between samples. Some chromosomes presented a larger number of fragments (BTA1, BTA19, BTA29), others had longer fragments (BTA4, BTA12, BTA17), while other ones showed an increased ROH accumulation over specific loci (BTA2, BTA7, BTA23, BTA29). Similar differences were observed in the analysis of 12 individuals produced by a similar inbred event (FPED3 = 0.125). The correlation between the fraction of the genome covered by ROH (FROH) and FPED was high (0.79), suggesting that ROH-based estimations are indicative of inbreeding levels. On the other hand, the correlation between FPED and the microsatellite-based inbreeding coefficient (FMIC) was only moderate (r = 0.44), suggesting that STR-based inbreeding estimations should be avoided. Similarly, we found a very low correlation (r = -0.0132) between recombination rate and ROH abundance across the genome. Finally, we performed functional annotation analyses of genome regions with significantly enriched ROH abundance. Results revealed gene clusters related to pregnancy-associated proteins and immune reaction. The same analysis performed for regions enriched with recently formed ROH (> 8 Mb) showed gene clusters related to flagellum assembly. In both cases, the processes were related to male and female reproductive functions, which may partially explain the reduced fertility associated with inbred populations.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari

Genetic characterisation of PPARG, CEBPA and RXRA, and their influence on meat quality traits in cattle

Background: Peroxisome proliferator-activated receptor gamma (PPARG), CCAAT/enhancer binding protein alpha (CEBPA) and retinoid X receptor alpha (RXRA) are nuclear transcription factors that play important roles in regulation of adipogenesis and fat deposition. The objectives of this study were to characterise the variability of these three candidate genes in a mixed sample panel composed of several cattle breeds with different meat quality, validate single nucleotide polymorphisms (SNPs) in a local crossbred population (Angus - Hereford - Limousin) and evaluate their effects on meat quality traits (backfat thickness, intramuscular fat content and fatty acid composition), supporting the association tests with bioinformatic predictive studies. Results: Globally, nine SNPs were detected in the PPARG and CEBPA genes within our mixed panel, including a novel SNP in the latter. Three of these nine, along with seven other SNPs selected from the Single Nucleotide Polymorphism database (SNPdb), including SNPs in the RXRA gene, were validated in the crossbred population (N = 260). After validation, five of these SNPs were evaluated for genotype effects on fatty acid content and composition. Significant effects were observed on backfat thickness and different fatty acid contents (P < 0.05). Some of these SNPs caused slight differences in mRNA structure stability and/or putative binding sites for proteins. Conclusions: PPARG and CEBPA showed low to moderate variability in our sample panel. Variations in these genes, along with RXRA, may explain part of the genetic variation in fat content and composition. Our results may contribute to knowledge about genetic variation in meat quality traits in cattle and should be evaluated in larger independent populations.Instituto de Genética Veterinari

Characterization of the bovine gene LIPE and possible influence on fatty acid composition of meat

LIPE is an intracellular neutral lipase, which is capable of hydrolyzing a variety of esters and plays a key role in the mobilization of fatty acids from diacylglycerols. The objectives of this study were to characterize the genetic polymorphism of bovine LIPE gene and to evaluate the possible association between three SNPs in the coding regions of this gene with the fatty acid composition of meat in a cattle population. Forty-three unrelated animals from different cattle breeds were re-sequenced and 21 SNPs were detected over approximately 2600. bp, five of these SNPs were novel. Three SNPs were selected, on the basis of evolutionary conservation, to perform validation and association studies in a crossbred cattle population. Our results may suggest a possible association of SNP1 with contents of oleic acid and total monounsaturated fatty acids (p < 0.01), and SNP2 and SNP3 with Heneicosylic acid content (p < 0.01), may be helpful to improve the quality of meat and improve health.Instituto de Genética Veterinari

Genetic variation in FABP4 and evaluation of its effects on beef cattle fat content

FABP4 is a protein primarily expressed in adipocytes and macrophages that plays a key role in fatty acid trafficking and lipid hydrolysis. FABP4 gene polymorphisms have been associated with meat quality traits in cattle, mostly in Asian breeds under feedlot conditions. The objectives of this work were to characterize FABP4 genetic variation in several worldwide cattle breeds and evaluate possible genotype effects on fat content in a pasture-fed crossbred (Angus-Hereford-Limousin) population. We re-sequenced 43 unrelated animals from nine cattle breeds (Angus, Brahman, Creole, Hereford, Holstein, Limousin, Nelore, Shorthorn, and Wagyu) and obtained 22 single nucleotide polymorphisms (SNPs) over 3,164 bp, including four novel polymorphisms. Haplotypes and linkage disequilibrium analyses showed a high variability. Five SNPs were selected to perform validation and association studies in our crossbred population. Four SNPs showed well-balanced allele frequencies (minor frequency &gt; 0.159), and three showed no significant deviations from Hardy-Weinberg proportions. SNPs showed significant effects on backfat thickness and fatty acid composition (P &lt; 0.05). The protein structure of one of the missense SNPs was analyzed to elucidate its possible effect on fat content in our studied population. Our results revealed a possible blockage of the fatty acid binding site by the missense mutation.Instituto de Genética Veterinari