Masters Degrees (Genetics)

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Browsing Masters Degrees (Genetics) by Advisor "Jansen, R."

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    Genetic connectivity, population dynamics and habitat selection of the southern ground hornbill (Bucorvus leadbeateri) in the Limpopo province
    (University of the Free State, 2011-03) Theron, Nicholas Terence; Kotze, A.; Grobler, J. P.; Jansen, R.
    Southern ground hornbills (Bucorvus leadbeateri) (SGH) are co-operative breeders that occur in groups of 2-9 individuals. Long life spans, large territory sizes (100km²), and low reproductive rates render these birds vulnerable to threats such as loss of habitat, persecution for their habit of breaking windows through territorial aggression, poisoning and loss of suitable nesting sites. As a result, SGH are listed as vulnerable in the red data book of South Africa as well as globally. The main objective of this study was to contribute to our overall understanding of the ecology and biology of the SGH for conservation planning. Data collection was completed in the nonprotected, semi-arid landscape of the Limpopo Valley from June 2008 - September 2009. The seasonal habitat use by a group of SGH, seasonal abundance (numbers) and biomass (volume) of invertebrates using pitfall and sweep net methods was investigated. Furthermore, a total of eight groups and 23 birds were captured in the Limpopo Valley and different statistical analysis were performed to investigate levels of inbreeding, relatedness, sex-biased dispersal and the effects the recent re-colonisation has had on the genetic structure of SGH in the Limpopo Valley. Finally the genetic variation of the species in the rest of Africa was determined using samples from Kenya, Tanzania and three populations in South Africa namely the Limpopo Valley, Kruger National Park (KNP) and Kwa Zulu-Natal (KZN). Genetic analysis revealed SGH have retained comparatively high levels of genetic diversity, even though there are indications of genetic bottlenecks in the Limpopo, KNP and Kenyan populations. The SGH populations studied were grouped into two clusters corresponding to the geographic origin of samples. The birds from Tanzania and Kenya clustered together while the KNP and KZN birds clustered together with the Limpopo population grouping more or less equally between the Kenyan/Tanzanian and South African populations. A large percentage of genetic variation was found within populations while among population variation was low, indicating there is little molecular evidence for the presence of SGH subspecies. The overall home range of one group was approximately 20 000 ha while seasonal home ranges varied between 5000 ha in winter to 13 500 ha in summer. The response of organisms to environmental variables in this extremely seasonal habitat was further revealed by the positive correlations found between the number of invertebrates with mean monthly maximum and minimum temperatures, and the volume of invertebrates with mean monthly rainfall. No significant differences were found between numbers and volume of invertebrates per order, between sites, which was expected in this homogenous vegetation type dominated by mopani shrub and trees (Colophospermum mopane). The re-colonisation of the Limpopo Valley was shown to have occurred by a number of unrelated individuals. This was demonstrable by very low levels of inbreeding and average relatedness of the population, as well as the favourable levels of heterozygosity across age and sex categories. Within group relatedness was high with juveniles related to at least one parent from their natal group. Insights were also gained into the breeding behaviour of SGH, providing evidence for the first time that SGH are not as monogamous as previously thought, with two instances of extra pair copulations recorded between four groups. This study shows that a holistic approach combining genetic techniques, radio telemetry studies and ecological principles has great potential to further investigate SGH, thereby contributing to the preservation of this enigmatic species of the savannah biome.
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    Insights into the genetics of the Ground Pangolin (Smutsia temminckii)
    (University of the Free State, 2013-02) De Beer, Christle; Kotzé, A.; Dalton, D.; Ehlers, K.; Jansen, R.
    English: Little is known about the molecular genetic variation of Ground Pangolin populations in South Africa. In this study it was attempted to assess the genetic diversity of the populations, but this could not be achieved due to insufficient cross‐species markers amplification. It should, however, be emphasized that the molecular work done in this study is novel, and that the results found during this research are key foundations for future studies. During sample collection it was found that three main populations of Ground Pangolins exist in South Africa in the Eastern, Western and Central parts of the country. Isolation protocols have been optimized, and it has been shown that noninvasive samples yield good quality and quantity DNA that is usable for down‐stream applications and perform as well as invasive samples. The PCR protocol was optimized, and the results from the optimization chapter will be of assistance when species‐specific markers are optimized. This study has also shown the need for the development of species‐specific markers, and the use of said markers will give a better indication of the genetic diversity of the Ground Pangolin populations in South Africa. From the statistical analysis it would seem that there are some correlations between the three sampling localities which may indicate a population divergence at some point. Based on the genetic diversity results, it appears that the diversity within Ground Pangolin populations is much lower based on the markers tested than in Malayan Pangolin populations. This will however have to be confirmed with species‐specific markers.