Indigenous domestic breeds as reservoirs of genetic diversity: the Argentinean Creole cattle

Abstract

Contrary to highly selected commercial breeds, indigenous domestic breeds are composed of semi-wild or feral populations subjected to reduced levels of artificial selection. As a consequence, many of these breeds have become locally adapted to a wide range of environments, showing high levels of phenotypic variability and increased fitness under natural conditions. Genetic analyses of three loci associated with milk production (alpha(S1)-casein, kappa-casein and prolactin) and the locus BoLA-DRB3 of the major histocompatibility complex indicated that the Argentinean Creole cattle (ACC), an indigenous breed from South America, maintains high levels of genetic diversity and population structure. In contrast to the commercial Holstein breed, the ACC showed considerable variation in heterozygosity (H(e)) and allelic diversity (A) across populations. As expected, bi-allelic markers showed extensive variation in He whereas the highly polymorphic BoLA-DRB3 showed substantial variation in A, with individual populations having 39-74% of the total number of alleles characterized for the breed. An analysis of molecular variance (AMOVA) of nine populations throughout the distribution range of the ACC revealed that 91.9-94.7% of the total observed variance was explained by differences within populations whereas 5.3-8.1% was the result of differences among populations. In addition, the ACC breed consistently showed higher levels of genetic differentiation among populations than Holstein. Results from this study emphasize the importance of population genetic structure within domestic breeds as an essential component of genetic diversity and suggest that indigenous breeds may be considered important reservoirs of genetic diversity for commercial domestic species.

African and European mitochondrial haplotypes in South American Creole cattle

“…An early indication of the influence of African breeds in the origin of Creole cattle is given in Giovambattista et al (2001), which describes the existence of two particular alleles of BoLA-DRB3 in Argentinean Creole cattle that were never mtDNA diversity in South American cattle PM Mirol et al detected in European breeds, but were reported in African indigenous breeds.…”

“…Previous studies based on polymorphism at loci related to milk production and immune response and on microsatellites have detected genetic structure among the Argentinean and Bolivian populations of cattle (Liró n et al, 2000; Giovambattista et al, 2001). An AMOVA based on the mitochondrial sequences was conducted in order to analyse the distribution of this variability.…”

“…During the 19th and 20th centuries, as a result of the introduction of highly selected European and Zebu commercial breeds, populations of Creole cattle suffered a severe reduction in number, and their distribution became restricted to marginal regions. Nowadays, ACc are distributed in semi-isolated populations of few individuals and low levels of gene flow (Giovambattista et al, 2001). They have been bred in semiwild conditions with low levels of artificial selection almost from their origin, suggesting that their genetic characteristics probably reflect very closely the original cattle brought to America from Spain.…”

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

“…The F ST and the exact test for genetic differentiation showed a significant subdivision of the Bolivian and Argentine Creole cattle population. This heterogeneous genetic pattern seems to be a major characteristic of American Creole breeds (Russell et al, 2000;Giovambattista et al, 2001) and could be the consequence of the subdivision of Creole cattle from this region into small herds, isolated or with a low degree of gene flow among them, and adapted to a wide range of environments. In concordance with this hypothesis, a lower level of average heterozygosity was observed in the Patagonian Creole cattle breed, which is the most isolated population.…”

Landscape genomic approach to detect selection signatures in locally adapted Brazilian swine genetic groups

“…2001) and, principally, source of traits selected and fixed mainly by the influence of the environment (Hall & Ruane, 1993). Mirkena et al.…”