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Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 62-65).

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Thesis (Ph. D.)--University of Adelaide, Dept. of Plant Science, 1997. / Chapter 2.7 (4 leaves) is contained in pocket on back cover. Includes bibliographical references (leaves 150-170).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 50-52).

A thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the Degree of Doctor of Philosophy. / Y chromosome DNA and mitochondrial DNA (mtDNA) variation were examined in Ugandans, Zambians, Biaka Pygmies and non-Pygmies from the Central African Republic. Y chromosome DNA variation was also examined in populations from the Democratic Republic of Congo. Data generated in this study were analysed together with published data to (1) clarify the understanding of the overall patterns of haploid genetic variation in Africa; (2) examine genetic affinities among central African and other African populations; (3) assess the concordance of haploid markers with different mutation rates in assessing population affinities; (4) compare male and female migration rates in African populations; and (5) refine theories regarding the prehistory of central Africa populations based on linguistics and archaeology. Sixteen biallelic and eight microsatellite Y-specific markers were examined in 369 central African individuals. Eleven Y chromosome haplogroups (HGs A, B*, B-M150, B-Ml 12, B- M211, E-M191, E-M2, E-M35, E-M40, FJ and R) and 174 compound haplotypes were identified. The mtDNA 9-bp deletion, 3592 Hpal and 10397 Alul restriction polymorphisms, and two hypervariable regions (HVRs) were examined in 397 individuals. A total of 246 mtDNA types were identified and classified into 19 mtDNA subhaplogroups. Using Y chromosome data, central African populations shared close genetic affinities with each other and with populations from west and southern Africa. Extensive unidirectional Y chromosome gene flow from non-Pygmy populations to Biaka Pygmies was observed. Using mtDNA data, central African non-Pygmy populations shared close genetic affinities with each other and with populations from west, east and southern Africa. MtDNA studies indicated almost complete maternal genetic isolation of Biaka. Overall, using both mtDNA and Y chromosome data, pan-African populations were best grouped by geographic rather than by linguistic criteria. Different mtDNA and Y chromosome data types revealed similar genetic relationships among African populations. Female migration rates appear to have exceeded male migration rates in non-Pygmy central African populations in this study, whilst the opposite was found in Biaka Pygmies. Data types at different levels of resolution suggested that male and female migration rates in Africa may have differed over time, and may not have been significantly different. This research has provided new insights into the complex demographic history that shaped the present-day genetic landscape of central African populations. / WHSLYP2016

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Chapter 2.7 (4 leaves) is contained in pocket on back cover. / Bibliography: leaves 150-170. / v, 178 leaves, [7] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1997

A higher level of efficiency in the production of doubled-haploids must be achieved if this procedure is to be beneficial in plant improvement. Of equal importance is the development of protocols, which are not genotypic specific and result in progeny that represent a random sample of gametes from the parental lines. To address these issues seven diverse winter wheat genotypes and a spring wheat, previously shown to be responsive in haploid plant production from anther culture, represented the experimental material. Two methods of generating haploid plants were employed. These were anther culture and the intergeneric hybridization of wheat with maize. Three induction media (MN6, P2 and Liang's) in liquid and semi-solid forms were employed with anther culture a direct culture. A modified floret culture along with different concentrations (20 and 100 ppm) and mode of application of 2,4-D were examined for the wheat x maize approach, Measurements included callus and embryo production and haploid plantlet regeneration. Two winter genotypes 'Gene' and 'Yamhill' did not respond to the anther culture methodology. For responsive genotypes MN6 was superior to P2 and Liang's medium for the traits measured. In contrast 'Chris' the spring wheat was more responsive for plantlet regeneration on P2 medium. No differences in haploid plantlet regeneration for the traits were observed between liquid and semi-solid medium forms. For the wheat x maize approach, direct culture was superior to the modified floret culture for embryo and haploid plantlet production. No differences were found in either 2,4-D concentration or whether 2,4-D was applied through tiller injection or placed as droplets on the florets. The wheat x maize approach was superior to anther culture for both embryo and green haploid plant production based on the number of florets used. Albino plants were produced in all responsive genotypes with anther culture. In contrast, no albino plants were regenerated with the wheat x maize approach. All genotypes were responsive for both embryo production and haploid plant regeneration in the intercrossing approach. In addition no regeneration distortion was observed for specific population employing this protocol. The wheat x maize approach was superior to anther culture for embryo production. This was also true for green haploid production based on the number of florets used. A higher proportion of albino plants was also observed when anther culture was employed. A further attribute of the wheat x maize approach was that all genotypes tested were responsive to embryo and haploid production. It was also revealed that no segregation distortion was present in three doubled haploid populations developed from wheat x maize crosses. / Graduation date: 1999

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