Agriculture

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Browsing Agriculture by Author "Hlophe, Sambulo Revelation"

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    Genetic variation between and within six selected South African sheep breeds using random amplified polymorphic DNA and protein markers
    (2011) Hlophe, Sambulo Revelation; Kunene, N.W.; Bezuidenhout, C.C.; Opoku, A.R.
    Six South Africa sheep breeds comprised of indigenous, imported and locally developed sheep were sampled. These breeds include Nguni sheep (Zulu, Swazi and Pedi), South African Merino, Damara and Dorper. Nguni goats were used as an out group. The first objective of this study was to determine the intra and inter-population genetic relationships among six South African (SA) sheep breeds using random amplified polymorphic DNA (RAPD) and protein markers. The second objective was to compare the efficiency between RAPD and protein markers in assessing the genetic variation. The Nei‟s genetic distance produced by the RAPD analysis ranged from 0.0430 – 0.1193 for the six selected sheep breeds. The results indicated that Zulu and Swazi breeds were the most genetically identical with a genetic distance of 0.0430. The second closest sheep breeds were the SA Merino and Damara with a genetic distance of 0.0595. The Pedi was related to the Dorper sheep breed with a genetic distance of 0.0814. The greatest genetic distance was between the Pedi and the SA Merino (0.1193) indicating that these two breeds are relatively distant from one another. Genetic identity was the largest (0.9579) between Swazi and Zulu breeds, followed by 0.9423 between SA Merino and Damara breeds. On the UPGMA dendogram the Zulu sheep formed a cluster with the Swazi sheep and the Damara clustered with the SA Merino. The Nguni goats did not cluster with the sheep breeds. The degree of genetic similarity within the sheep breeds ranged from 66.48 - 88.48 percent. The relationship within the Zulu sheep breed was 72.77%, Pedi 70.76%, Dorper 75.38% and Damara 83.24%. The Swazi sheep breed demonstrated the lowest percentage (66.48%) of genetic similarities between the individuals. On the other hand, the SA Merino breed with 88.48% showed the highest percentage of genetic similarity. When using the iso-enzymes of transferrin, the Damara and SA Merino formed a cluster with a genetic similarity of 97.13%. Just as in the RAPD results, the Pedi did not form a cluster with other Nguni sheep. The transferrin profile was able to characterise the Nguni goats as an out group species. The dendogram constructed using the data of the protein profile could not differentiate clearly between the sheep breeds and the Nguni goats. It can be concluded that although genetic relationships exist, the genetic distances vary among the six sheep breeds. The RAPD analysis demonstrated that these breeds can be treated differently. The genetic variation gave an indication that some breeds such as South African Merino are more uniform. The study showed that the RAPD markers can be used as a tool to estimate the genetic diversity and phylogenetic relationships among breeds of sheep. However, the protein markers must be used with caution. It is recommended that more research should be done to determine the genetic origin of the three Nguni sheep breeds (Zulu, Swazi and Pedi).