No abstract

No abstract

Background: indigenous breeds are important for poor farmers because of their natural selection against harsh environments and adaptation to regional conditions. However, inbreeding of indigenous sheep populations has increased in Colombia due to indiscriminate cross-breeding with foreign animals and lack of reproductive controls, with subsequent loss in productivity, which poses a great risk for the conservation of valuable genes. Objective: to determine the genetic diversity in Colombian indigenous sheep by using a panel of 10 microsatellite molecular markers. Methods: blood samples from 362 individuals from 43 farms in 11 Colombian provinces were genotyped and analyzed for a panel of 10 microsatellite markers. Results: a total of 134 alleles were found (13.4 alleles/locus on average) with a range of observed and expected heterozygosity of 0.428 to 0.831 and 0.615 to 0.855, respectively, and 0.742 polymorphic information content (PIC). The average Wright F-statistics (F IS ) of the breeds was 0.107, suggesting moderate levels of inbreeding. Colombian sheep showed a low level of genetic differentiation among breeds (F ST = 0.054) and STRUCTURE analysis showed complex patterns of admixture in the breeds. Conclusion: overall, Colombian sheep have high genetic variability, which is very important for future conservation programs and genetic improvement.

Colombia cuenta con tres razas de cerdos criollos (San Pedreño, Zungo y Casco de Mula), los cuales se encuentran en el país hace 500 años aproximadamente y están en riesgo de desaparecer debido a sus reducidas poblaciones y al uso preferente de razas foráneas mejoradas en los sistemas de producción. Para conservar las razas criollas se crearon los bancos de germoplasma, cuyas poblaciones se han mantenido como núcleos cerrados. El objetivo del estudio fue realizar un análisis de pedigrí para caracterizar la estructura genética de la población de cerdos San Pedreño del banco de germoplasma. Información genealógica colectada entre 2008-2017 se analizó para estimar el intervalo generacional, nivel de integridad del pedigrí, consanguinidad y evolución a través del tiempo. Los animales nacidos entre 2015 y 2017 se seleccionaron como población de referencia para estimar el tamaño efectivo poblacional y parámetros derivados de la probabilidad del origen genético. El intervalo generacional promedio para el periodo estudiado fue de 2.13 años y la consanguinidad general de 4.66%. Para la población de referencia, la consanguinidad fue del 6.73% y el tamaño efectivo poblacional de 25.31, en tanto que el número efectivo de fundadores y ancestros fue de 13 y 7 individuos, respectivamente; lo que ha conllevado a cuellos de botella en la población. Los resultados indican que para mantener la variabilidad genética y reducir los niveles de consanguinidad es necesario incluir individuos no emparentados de otras poblaciones.

The Blanco Orejinegro (BON) breed is one of the seven Colombian Creole cattle breeds, which descends directly from Spanish cattle brought to the Americas during the conquest period. Currently, most of the Creole cattle breeds in Colombia are at risk of disappearing due to the use of foreign breeds and absorbent crosses towards the Zebu and because of this, a germplasm bank was created to preserve them. The BON population kept in this germplasm bank has remained as a closed nucleous over time, and this can affect the conservation of its genetic variability. The objective of this study was to characterize the genetic structure of the BON population maintained in the germplasm bank using pedigree analysis. Genealogical information collected between 1980 and 2019 was used to estimate generational interval, level of pedigree integrity, inbreeding, and its evolution over time. The animals born between 2015 and 2019 were selected as the reference population to estimate the effective population size and parameters derived from the genetic origin probability. The average generation interval for the period studied was 4.58 years, and the general inbreeding was 1.32%. For the reference population, the inbreeding was 2.88%, and the effective population size was 123.75, while the effective number of founders and ancestors was 55 and 38, respectively. The results indicate that the population has a good genetic diversity and low levels of inbreeding. The use of a larger number of breeder males is recommended to conserve the population over time.