Investigating prolificacy as a trait to sustainability in smallholder sheep farming systems in South Africa

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dc.contributor.advisorMolotsi, Annelin H. en_ZA
dc.contributor.authorBooysen, Vernonen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Animal Science.en_ZA
dc.date.accessioned2023-03-07T11:36:37Z
dc.date.accessioned2023-05-18T07:16:39Z
dc.date.available2023-03-07T11:36:37Z
dc.date.available2023-05-18T07:16:39Z
dc.date.issued2023-03
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2023. en_ZA
dc.description.abstractENGLISH ABSTRACT: Characterisation of genes related to prolificacy is important for sustainable genetic improvement of indigenous sheep breeds in smallholder systems in South Africa. It is known that indigenous sheep are more robust and able to reproduce in adverse conditions in comparison to exotic sheep breeds. Genetic mutations occur commonly within genes and are responsible for the observed phenotypic variation between breeds within a species. The first objective of this study was to determine whether there were any genetic mutations between indigenous breeds in known fecundity genes, growth differentiation factor 9 (GDF9) and bone morphogenetic protein receptor type 1B (BMPR1B), in four South African indigenous sheep breeds. The second objective was to elucidate the phylogenetic relationship between these breeds based on the sequence information of the two genes under investigation. A total of 52 blood samples were collected from four sheep breeds (Karakul=8; Damara=8; Zulu=18; Pedi=18). Unlabeled forward and reverse primers were used to amplify GDF9 and BMPR1B genes. The results revealed point mutations between sheep breeds in the GDF9 and BMPR1B gene compared to that of the Ovis aries consensus sequence found in GenBank. From the 52 animals sampled, there were 13 individuals that had point mutations for the GDF9 gene and 7 individuals for the BMPR1B gene. Mutations of GDF9 gene, (c.142C>T) and (c.151G>C), were detected in individuals of the Karakul, Damara, and Zulu sheep. The results also show that the BMPR1B gene has a mutation at position (c.80G>C) between individuals of the Zulu and Pedi sheep. Molecular phylogenetic analysis for both genes using the Maximum Parsimony method indicates relatedness between the Zulu and Pedi sheep. The Damara and Karakul breeds also show more relatedness based on the two gene sequences. The phylogenetic analysis provides useful information for understanding the relationships between indigenous breeds and the differences in the expression of reproduction genes. Polymorphism between and within the sheep breeds could be an indication of genetic variation that is possibly associated with higher prolificacy in indigenous sheep breeds. Prolificacy will become increasingly important for the sustainability of sheep farming systems in terms of higher reproduction performance, especially for smallholder sheep farmers with indigenous breeds that contain valuable genetic resources.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Karakterisering van gene wat verband hou met reproduksie is belangrik vir volhoubare genetiese verbetering van inheemse skaaprasse wat deur kleinboere in Suid-Afrika aangehou word. Dit is bekend dat inheemse skaaprasse meer robuust is en in ongunstige toestande kan voortplant in vergelyking met eksotiese skaaprasse. Genetiese mutasies kom algemeen binne gene voor en is verantwoordelik vir die waargenome fenotipiese variasie tussen rasse binne 'n spesie. Die eerste doelwit van hierdie studie was om te bepaal of daar genetiese mutasies voorkom in bekende reproduksiegene, groeidifferensiasiefaktor 9 (GDF9) en beenmorfogenetiese proteïenreseptor tipe 1B (BMPR1B), tussen vier Suid-Afrikaanse inheemse skaaprasse. Die tweede doelwit was om die filogenetiese verwantskap tussen hierdie skaaprasse toe te lig, gebaseer op die inlighting van die geen-volgorde van die twee gene wat ondersoek word. Altesaam 52 bloedmonsters is uit vier skaaprasse (Karakoel = 8; Damara = 8; Zoeloe = 18; Pedie = 18) versamel. Ongemerkte voorwaartse en terugwaartse primers is gebruik om GDF9- en BMPR1B -gene te verleng. Die resultate dui op puntmutasies tussen skaaprasse in die GDF9- en BMPR1B -geen in vergelyking met dié van die Ovis aries konsensus geen-volgorde wat in GenBank voorkom. Van die 52 diere wat geneem is, was daar 13 individue met puntmutasies vir die GDF9-geen en 7 individue vir die BMPR1B-geen. Mutasies van GDF9 -geen (c.142C> T) en (c.151G> C) is by individue van die Karakoel-, Damara- en Zoeloe -skape opgespoor. Die resultate toon ook aan dat BMPR1B -geen mutasie (c.80G> C) tussen individue van die Zoeloe- en Pedie -skape voorgekom. Molekulêre filogenetiese analise vir beide gene met behulp van die ‘Maximun Parsimony’ metode dui verwantskap aan tussen die Zoeloe- en Pedie-skape.. Die Damara- en Karakoelrasse toon ook ‘n sterk verwantskap gebaseer op die twee gene. Die filogenetiese analise verskaf nuttige inligting om die verwantskappe tussen inheemse skaaprasse en die verskille in die uitdrukking van reproduksiegene te verstaan. Polimorfisme tussen en binne die skaaprasse kan 'n aanduiding wees van genetiese variasie wat moontlik geassosieer word met hoër vrugbaarheid in inheemse skaaprasse. Reproduksie sal toenemend belangrik word vir die volhoubaarheid van skaapboerderystelsels in terme van hoër reproduksieprestasie, veral vir kleinskaapboere met inheemse skaaprasse wat hoë genetiese diversiteit in hul reproduksiegene bevat.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentxiii, 43 pages : illustrations, mapsen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/127334
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshSheep farming -- South Africaen_ZA
dc.subject.lcshSmallholder farming systemsen_ZA
dc.subject.lcshSheep -- Breeding -- Genetic aspectsen_ZA
dc.subject.lcshSustainability -- Agricultureen_ZA
dc.subject.lcshSustainable farming -- South Africaen_ZA
dc.subject.lcshFarms, Small -- South Africaen_ZA
dc.subject.nameUCTDen_ZA
dc.titleInvestigating prolificacy as a trait to sustainability in smallholder sheep farming systems in South Africaen_ZA
dc.typeThesisen_ZA
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