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

Abstract

The ancestors of Uruguayan Creole cattle were introduced by the Spanish conquerors in the XVII century, following which the population grew extensively and became semi-feral before the introduction of selected breeds. Today the Uruguayan Creole cattle genetic reserve consists of 575 animals. We used the tetra primer amplification refractory mutation system polymerase chain reaction (ARMS-PCR) to analyze the k-casein, b-casein, aS1-casein and a-lactoalbumin gene polymorphisms and restriction fragment length polymorphism PCR (RFLP-PCR) for the b-lactoglobulin and the acylCoA:diacyl glycerol acyltransferase 1 (DGAT1) genes. The k-casein and b-lactoglobulin genes presented very similar A and B allele frequencies, while the as1-casein and a-lactoalbumin gene B alleles showed much higher frequencies than the corresponding A alleles. The b-casein B allele was not found in the population sampled. There was a very high frequency of the DGAT1 gene A allele which is associated with low milk fat content and high milk yield. All loci were in Hardy-Weinberg equilibrium and the level of heterozygosity agreed with the high genetic diversity observed in a previous analysis of this population. Preservation of the allelic richness observed in the Uruguayan Creole cattle should be considered for future dairy management and livestock genetic improvement. The results also emphasize the value of the tetra primers ARMS-PCR technique as a rapid, easy and economical way of genotyping cattle breeds for milk gene single nucleotide polymorphisms.

Characterization of the DGAT1 gene in the Indian buffalo (Bubalus bubalis)

“…All the buffalo breeds (Indian and Chinese) as well as Bos indicus cattle Lacorte et al 2006;Tantia et al 2006) have a fixed K allele, which may be responsible for higher milk fat in buffalo and B. indicus cattle. Rincón et al 2006 found that Uruguayan Creole cattle (B taurus) had DGAT1 allele frequencies (A allele = 0.89; K allele = 0.11) similar to B taurus beef breeds. The B. taurus breeds selected for milk production show more variation in DGAT1 with allele frequencies of some breeds being close to 0.50 for each allele (e.g.…”

Marcadores moleculares asociados al veteado de la carne en bovinos Criollos uruguayos

“…Los resultados obtenidos para el gen DGAT1 muestran una clara predominancia del alelo y genotipos asociados con una menor proporción de grasa y coinciden con lo hallado previamente en una muestra menor de Criollos Uruguayos puros (Rincón et al, 2006). Esta tendencia es la usual en razas de Bos taurus, a diferencia de lo que ocurre en razas cebuinas y en razas lecheras seleccionadas para un mayor contenido graso en la leche, como Jersey, en las cuales se observa una muy alta frecuencia del alelo K (Thaller et al, 2003;Kaupe et al, 2004;Casas et al, 2005;Gill et al, 2009).…”

“…Los genes DGAT1 y TG se analizaron mediante PCR-RFLP, utilizando las enzimas de restricción Mwo I (Rincón et al, 2006) y Psu I (Thaller et al, 2003), respectivamente. El protocolo de amplificación utilizado incluye 2,5 µl de buffer de PCR 10X, 1,5 µl de MgCl2 25 mM, 1,3 µl de DMSO, 1,0 µl de dNTPs 10 mM, 1,0 µl de cada cebador 10 pmol, 0,2 µl de Taq polimerasa 5 UI, más 10 µl de ADN genómico, en un volumen final de 25 µl.…”

“…Estos animales se encuentran aislados reproductivamente de otras poblaciones bovinas y no están sometidos a una rigurosa selección artificial. Estudios previos con microsatélites revelan una alta diversidad genética y bajo índice de endogamia (He>0,60; F IS = 0,02; Armstrong et al, 2006), así como gran diversidad alélica en genes relacionados a producción de leche y derivados (Rincón et al, 2006). En la década de 1960 se produjo una migración de algunos de estos animales a establecimientos ganaderos del norte del país de los Departamentos de Cerro Largo y Rivera, en zonas fronterizas con Brasil.…”

Genetic diversity analysis of the Uruguayan Creole cattle breed using microsatellites and mtDNA markers

“…The management of the population since then has consisted in limiting the number of breeding males and the periodic culling of a certain number of animals as a way of controlling population size. Different molecular markers have been analyzed in this population, including a set of 18 microsatellite loci in breeding bulls (Armstrong et al, 2006a), RAPD markers (Rincón et al, 2000), the polymorphic region of the DRB3.2 gene of the major histocompatibility complex and major genes related to milk and beef production (Postiglioni et al, 2002;Rincón et al, 2006;Armstrong et al, 2011).…”