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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Genetic variation of Kappa-casein in South African goats

Scheepers, Robyn Clair 21 October 2009 (has links)
Milk protein polymorphisms have a significant influence on milk quantity and composition. Kappa-casein is of special interest due to its known relationship with milk quality. In goats, a number of allelic variants have been identified, primarily classified into two groups. Group BIEF alleles (D, E, K, and M) have been shown to have a positive effect on milk yield and technological properties, while group AIEF, the remaining alleles, have a less positive influence on milk composition. The aim of this study was to investigate genetic variation in the kappa-casein genotype of South African goats. PCR-RFLP and DNA sequencing were performed on 68 and 77 samples, respectively. In addition, 84 milk samples were analyzed for milk composition. RFLP analysis revealed that the A and/or B alleles were the most frequent in the populations studied. A frequency of 0.00 was observed for the BIEF variants using DNA sequencing. In all goat types included, the B allele was the most common, with frequencies ranging from 60% in SA Boer goats to 100% in Saanens. The B’ allele had lower frequencies of 0.357 and 0.207 in SA Boer goats and local goat types, respectively. The H allele was present at low frequencies in local goat types (10.3%) and in SA Boer goats (3.6%), but was absent in Saanens. AMOVA results indicated that most of the total variation occurred within populations (80.66%) with the remainder of the variation (FST = 0.1934; p < 0.01) occurring due to genetic differences between populations. / Dissertation (MSc(Agric))--University of Pretoria, 2009. / Animal and Wildlife Sciences / unrestricted

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