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

Abstract

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 α S1 -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.

Analysis of the population structure of Uruguayan Creole cattle as inferred from milk major gene polymorphisms

“…The a s1 -CN polymorphism showed a high B allele frequency (0.8) and a low heterozygosity value (He = 0.2376) similar to that observed in Creole populations as well as in North American Holstein-Friesian cattle (Van Eenennaam and Medrano, 1990;Lirón et al, 2002).…”

“…Allelic variants of the k-CN, a s1 -CN and b-LG genes have also been analyzed in Argentinean and Bolivian Creole cattle (Lirón et al, 2002) and show similar frequencies to that observed in the Uruguayan Creole cattle. However, the Uruguayan Creole cattle allele distribution is even more similar to that seen in semi-wild Argentinean cattle (the Patagonian Creole) and to a Bolivian population (Saavedreño Creole) bred for dairy and beef production.…”

“…However, the Uruguayan Creole cattle allele distribution is even more similar to that seen in semi-wild Argentinean cattle (the Patagonian Creole) and to a Bolivian population (Saavedreño Creole) bred for dairy and beef production. Also, the expected heterozygosity of the k-CN (0.5028) and b-LG (0.5031) genes in Uruguayan Creole cattle is higher than that occurring in Argentinean and Bolivian Creole herds (Lirón et al, 2002).…”

Estructura y diversidad genética en vacas Holstein de Antioquia usando un polimorfismo del gen bGH

“…En la actualidad se conocen un amplio número de marcadores genéticos que pueden ser usados para evaluar la diferenciación poblacional (1). Entre estos marcadores se encuentran algunos relacionados con parámetros productivos en ganado de leche (2), como es el caso del polimorfismo en un solo nucleótido o SNP que son marcadores polimórficos que pueden ser reconocidos mediante varias técnicas (3), entre las cuales se encuentra la PCR (reacción en cadena de la polimerasa) asociada a RFLP (polimorfismo en la longitud de los fragmentos de restricción) (4).…”

“…Algunos parámetros poblacionales estimados usando el gen de bGH, permiten calcular las frecuencias genotípicas, alélicas y el flujo de genes entre las poblaciones para determinar su grado de diversidad y diferenciación (1). La determinación del equilibrio de Hardy-Weinberg (HW), la estimación de las frecuencias alélicas y genotípicas, posibilitan no solo determinar el comportamiento poblacional, sino que de acuerdo a las frecuencias de los alelos en la población permiten determinar la importancia de dicho polimorfismo en un programa de mejoramiento genético, ya que aquellos alelos que se encuentran casi fijados en una población tendrían diferente respuesta a la selección que aquellos alelos que se encuentran en proporciones intermedias.…”