Throughout the history of mankind, sheep have played a very important and unique part in the economies of the world. They have been a source of meat, milk, skins and fiber. They have become adapted to nearly every kind of husbandry, from nomadic types to intensively managed flocks on small farms and have thrived under nearly all climatic conditions, ranging from sub-artic regions of Greenland to hot areas of the mediterranean countries; from desert areas of Africa to wet lowland of England. Domestic sheep were introduced on the American continent by Spanish discovered and conquerors in 1493. (8, p.281) The other route by which they came was from England in 1607. (e, p. 21)

Student Number : 0416521T - MSc(Med) dissertation - School of Pathology - Faculty of Health Sciences / Fetal alcohol spectrum disorder (FASD) encompasses a range of conditions induced by prenatal alcohol exposure. Fetal alcohol syndrome (FAS) is the most severe of these conditions. FAS is characterised by discriminating facial features along with growth deficiencies and central nervous system abnormalities. FASD is a growing concern in South Africa, particularly in the Northern and Western Cape Provinces. In the Northern Cape, astounding prevalence rates of 122 and 73.8 per 1000 school entry children have been established for the towns of De Aar and Upington respectively. Studies involving twin concordance research and animal models have indicated that there is a genetic influence contributing towards FAS susceptibility in individuals. FAS is considered a complex disease whereby both genetic and environmental factors interact in disease pathogenesis. For this reason a case-control study involving the investigation of appropriate candidate genes was conducted. The neuronal migration pathway in the developing brain is targeted by prenatal alcohol exposure. The astrotactin (ASTN) and reelin (RELN) genes were selected for investigation based on their fundamental role in neuronal migration. A FAS case-control study involving 45 cases and 112 controls was conducted on the Northern Cape Coloured population. Four single nucleotide polymorphisms (SNPs) including missense and non-coding variants were selected within ASTN and four missense SNPs were selected within RELN. The study aimed to determine the genotype and allele frequencies of the variants within the case and control groups and to assess whether any association between the gene variants and the predisposition to FAS existed. Statistical analyses indicated a significant genotypic association (P= 0.049) between RELN’s rs607755 marker; the C/T genotype was more likely to be found amongst controls thus inferring a possible protective effect against FAS. A logistic regression model supported the above association by indicating the C/T genotype as being independently significant (P= 0.026). The most limiting factor of this study was the small sample size and consequent lack of power to detect genes with minor effects. It would therefore be suggested that the study be repeated once a larger sample size has been established. A larger sample size would increase the chances of detecting true associations between genes of minor effect and FAS, thus minimising false-positive associations from arising.

Human activity can affect the soil in ways which are traceable long after the land has been given over to other uses, and past land management practices can be reconstructed by investigation of these relict characteristics. In some regions the addition of fertilising materials to the arable soils has created artificially deepened anthropogenic topsoils which can be over 1m thick. Such relict soils are found all over the world, and are widespread in north-western Europe. This work focuses on the anthropogenic soils in the Northern Isles, which were formed from the Neolithic period up until the 20th century. Three multi-period sites were investigated using thin section micromorphology, organic/inorganic phosphate analysis, soil magnetism, particle size distribution, loss on ignition and soil pH. Current views of anthropogenic soil formation, based on pedological investigation and historical documentary sources, are that they are formed as a result of the addition of domestic animal manures and turf used as animal bedding to arable areas. This project sets out to test the hypothesis that in fact anthropogenic soils are the result of a wide range of formation processes which took place over extended periods of time. The hypothesis has been tested by analysing soils and associated middens of different dates, which have been sealed and protected by blown sand deposits. The results have shown that in the Neolithic period arable soils were created by cultivating the settlement's midden heaps as well as by adding midden material to the surrounding soils. In the Bronze Age human manure, ash and domestic waste were spread onto the fields around the settlements to create arable topsoils up to 35cm thick. In the Iron Age arable agriculture was intensified by selective use of organic manures on one of the sites investigated, but organic waste material was not used as efficiently as it was in later periods, and on both sites it was allowed to accumulate within the settlements. In the Norse period, when the intensive system used in historical times appears to have originated, organic waste may have been used more efficiently. These changes appear to reflect a greater organisation of land resources and manuring strategies and increased demand for arable production over time.