Estudio de asociación genómica para características de crecimiento en las razas bovinas Criollas Blanco Orejinegro y Romosinuano

Las características relacionadas con el crecimiento son de gran importancia para la industria del ganado de carne, dado que afectan de manera directa la rentabilidad de las ganaderías, debido a esto, hay un gran interés en la comprensión de la estructura genética que controla este tipo de rasgos, pues al incluir esta información en la valoración genética de los animales, es posible mejorar la precisión en los procesos de selección. En este estudio, información de 52mil Polimorfismos de Nucleótido Simple (SNP) obtenida a partir de dos poblaciones de ganado Criollo Colombiano (Blanco Orejinegro-BON y Romosinuano-ROMO), fue usada para desarrollar un estudio de asociación genómica (GWAS) para rasgos de crecimiento, basado en la metodología de single-step genomicBLUP, este GWAS permitió identificar 28 regiones de interés en la raza BON, y 26 regiones en la raza ROMO, que están asociadas con 53 posibles genes candidatos, que incluyen algunos con un rol conocido en la regulación del crecimiento, tales como LEPR (receptor de la leptina), HGF (factor de crecimiento de hepatocitos), LEP (leptina), TG (Tiroglobulina), Myf5 (factor miogénico 5) y PLAG1 (zinc finger); es de resaltar que en los cromosomas 14 y 23 se identificó dos regiones con efecto común para varias de las características evaluadas en las dos razas, esto sugiere que en estas regiones existen algunos genes candidatos con funciones asociadas a la regulación del crecimiento en este tipo de ganado. Estos resultados pueden ser incluidos en la evaluación genética de estas razas, para mejora la exactitud en la estimación de valores genéticos.Abstract. The growth traits are of great importance for the beef industry, since they directly affect the profitability of the herds, because of this, there is great interest in the understanding the underlying genomic structure influencing these traits, when using this information in the genetic evaluation programs, it is possible to increase the accuracy in the selection in livestock. In this study, information of 52k single nucleotide polymorphisms (SNPs) obtained from two populations of Colombian Creole Cattle (Romosinuano-ROMO and Blanco Orejinegro-BON) was used to perform a genome-wide association study (GWAS) for growth traits, based on the single-step genomic- BLUP methodology, this GWAS identified 28 genomic regions with important effect in BON breed, and 26 regions in ROMO breed, which were associated with 53 positional potential candidate genes, including some of them with a role in growth regulation, such as LEPR (leptin receptor), HGF (hepatocyte growth factor), LEP (leptin), TG (thyroglobulin), Myf5 (myogenic 5 factor), and PLAG1 (zinc finger). It is noteworthy that in chromosomes 14 and 23 there are two regions with common effects for traits evaluated in the two breeds, this suggests that in these regions there are some candidate genes with fuctions related to the regulation of body weight in this type of cattle. These results may be included in genetic evaluations of these breeds, to improve the accuracy in estimating breeding values.Maestrí

SNP Genotyping for Purity Assessment of a Forage Oat (Avena sativa L.) Variety from Colombia

Single nucleotide polymorphism (SNP) markers have multiple applications in plant breeding of small grains. They are used for the selection of divergent parents, the identification of genetic variants and marker-assisted selection. However, the use of SNPs in varietal purity assessment is under-reported, especially for multi-line varieties from the public sector. In the case of variety evaluation, these genetic markers are tools for maintaining varietal distinctness, uniformity and stability needed for cultivar release of multi-line or pure-line varieties of inbred crops. The objective of this research was to evaluate the purity and relationships of one original (AV-25) and two multi-line sub-populations (AV25-T and AV25-S) of the inbreeding species, oats (Avena sativa L.). Both sub-populations could be useful as forages in the central highland region of Colombia (\u3e2000 masl), such as in the departments of Boyacá and Cundinamarca, even though they were derived from an original composite mixture widely used in the mountainsides of the southern department of Nariño named Avena 25. Representative single plant selections (SPS) from the two sub-populations were grown together with SPS harvests from off-type plants (early and late) and plants from the original AV25 composite mixture, to determine their genetic similarity. Plants were genotyped by DNA extraction of a plateful of 96 individual plant samples and SNPs were detected for an Illumina Infinium 6K Chip assay. The data were used for the analysis of genetic structure and population relationships. The grouping observed based on the genetic data indicated that AV25-T and AV25-S were homogeneous populations and somewhat divergent in their genetic profile compared to the original AV25-C mix. In addition, to the two commercial, certified oat varieties (Cajicá and Cayuse) were different from these. The early and late selections were probable contaminants and could be discarded. We concluded that the use of SNP markers is an appropriate tool for ensuring genetic purity of oat varieties