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). kappa-casein, beta-lactoglobulin, growth hormone and prolactin were measured by PCR-RFLP, while alphaS1-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.
Highlights
American Creole cattleAnthropological and paleontological evidence shows that the first cattle were brought to America by Spanish conquerors starting in 1493 (Primo, 1992)
Tests for κ-casein (κ-cas), β-lactoglobulin (β-lg), and growth hormone (GH) genes were performed by PCRRFLP, according to the procedures proposed by Agrawala et al (1992), Medrano and Aguilar-Córdoba (1990), and
The FST index and the pairwise FST were used as estimators of genetic subdivision and genetic differentiation among the Creole cattle breeds studied. This parameter was calculated using the GENEPOP software package (Raymond and Rousset, 1995). Gene frequencies and their standard errors for each locus of the six Creole cattle breeds studied are given in tables 1 to 5
Summary
American Creole cattleAnthropological and paleontological evidence shows that the first cattle were brought to America by Spanish conquerors starting in 1493 (Primo, 1992). The founder populations of Creole cattle, introduced in America by the Spanish and Portuguese conquerors during the first 50 years of colonization, consisted of 300 to 1000 animals of Iberian origin (Primo, 1992; Wilkins et al, 1982). The Creole cattle were the only bovines bred in Latin America for more than 300 years, until selected European and Zebu breeds were introduced. American Creole cattle evolved under low levels of breeding management and, as a result of natural selection, became adapted to different environments, such as the tropical rainforest, the subtropical dry forest, the highland. Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, 60 y 118 s/n.
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