Genetic and phenotypic variation among four Nguni sheep breeds using random amplified polymorphic DNA (RAPD) and morphological features

摘要

This study was conducted to investigate phenotypic and genetic differentiation among the four Nguni sheep breeds. Sheep with two permanent incisors and above were sampled from areas, namely KwaZulu-Natal (Zulu sheep), Limpopo (Pedi sheep), Mozambique (Landim sheep) and Swaziland (Swazi sheep). The Dorper was used as an out-group. Eight morphometric variables were measured from each animal, and blood samples were collected (n = 50 per population) for genetic characterization. The mean body weights for sheep were 30.41 +/- 0.41, 35.34 +/- 0.43, 35.23 +/- 0.43, 37.63 +/- 0.42 and 52.84 +/- 0.30 for Swazi, Zulu, Landim, Pedi and Dorper, respectively. Morphometric cluster analysis showed the Landim, Swazi and Zulu breeds in one cluster. The Pedi sheep were closer to the Dorper than to the other Nguni sheep. Random amplified polymorphic DNA (RAPD) technique was used to assess genetic variation. Eight primers were selected for analysis based on band pattern quality, reproducibility and the presence of distinctive bands. The Swazi sheep formed a cluster with Zulu sheep, and the Pedi formed a cluster with the Dorper. These results confirm indications by other researchers that Pedi sheep are genetically distant from Zulu and Swazi sheep breeds. This could indicate the possibility of cross breeding Zulu and Swazi sheep as a possible conservation strategy to control inbreeding. The mtDNA should be analyzed to trace the relationships between Pedi and the three Nguni sheep breeds through maternal lines.