The Afrikaner is an indigenous South African breed of "Sanga" type beef cattle along with breeds such as the Drakensberger and Nguni. Six composite breeds have been developed from crosses with the Afrikaner. Additionally, Afrikaner has been the base from which exotic breeds were established in South Africa through backcrossing. The study examined genetic diversity of Afrikaner cattle by genotyping 1257 animals from 27 herds in different geographic areas of South Africa and Namibia using 11 microsatellite markers. Multiple-locus assignment, performed using the Bayesian clustering algorithm of STRUCTURE, revealed three underlying genotypic groups. These groups were not geographically localized. Across herds and markers, the proportion of unbiased heterozygosity ranged from 0.49 to 0.72 averaging 0.57; mean number of alleles per locus ranged from 3.18 to 7.09, averaging 4.81; and allelic richness ranged from 2.35 to 3.38, averaging 2.67. It is concluded that a low inbreeding level of 2.7% and a moderate to high degree of variation still persists within the Afrikaner cattle breed, despite the recent decline in numbers of animals.

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Following immunohaematopoietic stem cell transplantation, it is of importance to determine whether the new blood forming system is of recipient or donor origin and such phenotypic characterisation is called chimerism analysis. This is a dynamic process, which may be complete, mixed or split between compartments and in this way, plays an increasingly important role in predicting outcome for engraftment, rejection or residual disease predicating the need for pre-emptive immunotherapy. Based on recent workshop recommendations, peripheral blood cells have been used in the short tandem repeat (STR) assay to serially characterise the haematologic course and so evaluate the usefulness of this system. Forty-six patients from a single centre were followed serially for periods ranging between 3 and 60 months. The analysis was initially performed using the Applied Biosystems Profiler Plus Kit; currently, the Promega Powerplex 16 system is used. The overlap between the two assays has allowed for continuous comparison. The initial analysis was performed at 14 days post-transplant and repeated monthly. Stored DNA from the patient and donor was used to establish the pre-transplant profile. All post-transplant analyses were performed using peripheral blood. The results obtained were expressed as a percentage of the donor profile. To illustrate the ability of this technology, three representative profiles are described. In the first, stable engraftment is confirmed at 20 months with only donor pattern present. The second is intermediate, and while the patient is clinically disease free, there exists stable mixed chimerism at about 75% of donor cells. The third patient initially engrafted but the reappearance of recipient alleles presaged a haematological relapse; the latter is an indication for salvage with donor lymphocyte infusion and here this assay will be used to show the effectiveness of the intervention. These preliminary results show this to be a useful additional tool in monitoring post-transplant engraftment. As a basis for pro-active therapy, a larger study integrating the results of haematological and cytogenetic markers is planned.

The Afrikaner is one of three indigenous cattle breeds found in South Africa. Afrikaner cattle were originally extensively used for crossbreeding purposes and breed development. The objective of this study was to determine the genetic diversity of selected stud and commercial herds from the whole South African Afrikaner population, as well as to determine the genetic structure among these herds. Assignment methods (based on STRUCTURE software) revealed a real structure consisting of four genetic populations (K = 4). Estimates of genetic diversity did not support the hypothesis of significant loss of genetic diversity in any individual Afrikaner herd. Heterozygosity estimates ranged from 0.456 - 0.737 within individual populations, with an overall heterozygosity estimate of 0.568 for the Afrikaner breed. The average number of alleles per locus was regarded as being 2.67 - 7.78, with an average of 5.18 alleles per locus. It could be concluded that a moderate to high degree of variation is still present within the Afrikaner cattle breed, despite the recent decline in numbers of this indigenous breed.Keywords: Bos taurus africanus, heterozygosity, inbreeding, microsatellite markers

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