Resumen

ROSERO, Jaime A et al. Allelic frequency of the Kappa-Casein gene in Colombian and creole cattle breeds. Rev Colom Cienc Pecua [online]. 2012, vol.25, n.2, pp.173-182. ISSN 0120-0690.

Colombia has one of the most genetically diverse creole cattle populations, with eight creole breeds and two improved creole (Colombian) breeds. A high demand for meat and milk has led to the inevitable selection of highly productive cattle and the introduction of foreign breeds. Unfortunately, these breeds are often ill-suited for tropical conditions. These factors threaten the size of the creole livestock population, which is considered part of Colombia's national heritage. Objective: to estimate the allelic frequencies of the Kappa-Casein gene (CNS3) in Colombian creole cattle breeds (GCC). Methods: a total of 354 blood samples were taken from 30 animals of each of the following breeds: Blanco Orejinegro (BON), Caqueteño (CQT), Casanareño (CAS), Horned Costeño (Costeño con Cuernos, CCC), Chino Santandereano (ChS), Hartón del Valle (HV), Romosinuano (ROM), and Sanmartinero (SM), each representing the 8 established ''criollo'' (creole) breeds; the Lucerna (LUC) and Velasquez (VEL) representing the two Colombian improved breeds; and Brahman and Holstein as control breeds. DNA was extracted by a salting-out procedure and a 453 bp fragment on chromosome 6 was amplified by PCR. CSN3 alleles were identified using single strand conformation polymorphism (SSCP) and their sequence compared with those of the Genebank for Bos taurus and Bos indicus. Results: higher frequencies for allele variants of CSN3 A (0.39) and B (0.41) were found relative to the frequencies of I (0.038), G (0.095), A₁ (0.025), E (0.006), and N (0.006). The allele of interest (CSN3 B) had a high frequency in the CCC (0.81), ROMO (0.66), CQT (0.55), ChS (0.48), and VEL (0.43) breeds. Conclusions: these findings suggest that Colombian creole breeds harbor a high genetic diversity which enriches its gene pool and warrants future conservation efforts to protect its integrity.

Palabras clave : genetic variants; milk proteins; molecular markers; PCR-SSCP.

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