Thesis (Ph. D.)--University of North Texas, Dec., 2008. / Title from title page display. Includes bibliographical references.

This thesis examined the effectiveness of DNA fingerprinting analysis for paternity ascertainment and the establishment of relatedness of captive Asian elephants (Elephas maximas). Eighteen Asian elephants from three North .American zoos were examined. Thirteen of these elephants were wild caught. Relationships between these elephants and the remaining elephants born in captivity were known.

No description available.

published_or_final_version / abstract / Civil Engineering / Doctoral / Doctor of Philosophy

<p>The aim of this study was to investigate the forensic usefulness of various Y-chromosome short tandem repeat loci among South African sub-populations. Three different sets of Y-chromosome short tandem repeat loci were chosen for investigation.</p>

Roseate spoonbills are colonial nesting birds with breeding grounds extending from the United States Gulf coast to the pampas of Argentina. The U.S. population suffered a severe bottleneck from 1890 to 1920. The population's recovery was slow and partially credited to migrations from Mexican rookeries, but a gene pool reduction would be expected. Five polymorphic Spoonbill autosomal short tandem repeat (STR) loci [three (GAT)n, one (AAAG)n and one (GT)n] and one Z/W-linked microsatellite exhibiting sex-specific dimorphism were isolated and characterized. The Z/W-linked STR locus accurately confirmed the sex of each bird. Allelic profiles for 51 spoonbills obtained from Dallas (Texas), Fort Worth (Texas) and Sedgwick County (Kansas) zoos revealed a non-continuous distribution of allele frequencies, consistent with the effects of a population bottleneck. Allelic frequencies also differed significantly between the isolated zoo populations. Although extra-pair copulations were suspected and difficult to document, zoos commonly used observational studies of mating pairs to determine familial relationships among adults and offspring. STR parentage analysis of recorded family relationships excluded one or both parents in 10/25 cases studied and it was further possible to identify alternative likely parents in each case. Mistaken familial relationships quickly lead to the loss of genetic variability in captive populations. Here, a decreased heterozygosity (HO) in 2nd generation captive-bred birds was observed at 3 out of 4 loci evaluated. Although these results could not be statistically validated because of the small number of individuals available for study (15 wild birds with no offspring vs. eight 2nd generation captive birds), they are considered biologically important, as decreased HO is an indicator of inbreeding and this apparent decrease occurred within two generations of removal from the wild. Collectively, the evidence obtained from this study suggests that captive spoonbill populations are experiencing rapid loss of diversity from an already depleted wild gene pool.

Rice blast disease is caused by the ascomycete fungus Magnaporthe oryzae and is of economic importance worldwide, due to its wide geographical distribution and the severe yield losses it causes on cultivated rice. Understanding the population structure of M. oryzae is key to sustainable management of blast disease. In this study, a total of 290 M. oryzae isolates were collected from rice growing regions in Kenya including Central Kenya (Mwea irrigation scheme), Western Kenya (Ahero and Maugo irrigation schemes in Ahero and Homa-Bay respectively) and Coastal Kenya (Kwale). Initially, I undertook genotyping of a subset of Kenyan isolates by DNA sequence analysis of the internal transcribed spacer regions (ITS 1 and ITS 2) of the rRNA-encoding gene unit and by DNA fingerprinting using the Pot2 repetitive DNA element. Phylogenetic analyses based on ITS sequences clustered together isolates from Western and Coastal Kenya which were distinct from Central Kenya isolates. Cluster analysis based on 80% DNA fingerprint similarity, identified five clonal lineages designated KL1, KL2, KL3, KL4 and KL5 with most isolates belonging to lineages KL2, KL3, KL4. The clustering of isolates was region specific with Western and Coastal isolates closely related to each other and distinct from Central Kenya isolates. Distribution of mating type gene loci (MAT1.1 and MAT1.2) was determined using mating type gene specific primers. My results indicate that MAT1.1 is the predominant mating type and is distributed in all the rice growing regions of Kenya. MAT1.2 isolates were identified only in Coastal Kenya. I further undertook high throughput next-generation DNA sequencing of the genomes of 27 M. oryzae isolates from sub-Saharan Africa (SSA), including Kenya, Uganda, Tanzania, Benin, Togo, Nigeria and Burkina Faso and compared them to other sequenced strains from China, India, USA, Philippines, Thailand, Korea, Japan, France and French Guiana. Single nucleotide polymorphisms (SNPs) indicated that majority of East African isolates of M. oryzae clustered separately from West African isolates. African isolates clustered with isolates from India and China, indicating that rice blast in SSA may have originated from Asia. Pathotype analysis of Kenyan isolates was undertaken using a set of monogenic differential rice varieties, collectively harbouring 24 disease resistance genes. Rice blast resistance gene Pi-z5 conferred resistance to all the isolates tested. Other resistance genes that conferred resistance to majority of isolates tested include Pi-9, Pi-12(t), Pi-ta, Pi-ta2 and Pi-z. These resistance genes are suitable candidates for introgressing into commercially grown varieties in Kenya in combinations. I also investigated the population of M. oryzae isolates to identify cognate avirulence gene loci, including novel genes not yet reported. Finally, I evaluated rice varieties grown in Kenya for resistance to indigenous rice blast isolates under laboratory conditions. Rice variety Basmati 370 was susceptible to rice blast with varieties IR2793-80-1, BW 196, NERICA 1, NERICA 4, NERICA 10, and NERICA 11 showing some disease resistance. Varieties ITA 310 and Duorado Precoce were moderately tolerant to rice blast. This information is being used to develop a durable blast resistance strategy in sub-Saharan Africa.

Qi, Huijie = 用于脫氧核糖核酸分子精确识别的Förster共振能量转移与光电压效应相结合的DNA-量子点分子光电开关 / 齐慧杰. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Abstracts in English and Chinese. / Qi, Huijie = Yong yu tuo yang he tang he suan fen zi jing que shi bie de Förster gong zhen neng liang zhuan yi yu guang dian ya xiao ying xiang jie he de DNA-liang zi dian fen zi guang dian kai guan / Qi Huijie. / Abstract --- p.i / Acknowledgements --- p.iv / Table of contents --- p.v / List of Figures --- p.ix / List of Tables --- p.xiii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.1.1 --- Nanotechnology and nanomaterials --- p.1 / Chapter 1.1.2 --- "Semiconductor quantum dots: optical properties, preparation and applications" --- p.3 / Chapter 1.1.2.1 --- Preparation --- p.3 / Chapter 1.1.2.2 --- Applications --- p.5 / Chapter 1.1.3 --- Quantum dot-based DNA recognition --- p.10 / Chapter 1.1.3.1 --- Forster resonance energy transfer --- p.11 / Chapter 1.1.3.2 --- Bioimmobilization technique --- p.13 / Chapter 1.1.3.3 --- Highlights on Quantum dot-based DNA recognition --- p.14 / Chapter 1.2 --- Objective and methodology --- p.16 / Chapter 1.2.1 --- Objective --- p.16 / Chapter 1.2.2 --- General methodology --- p.17 / References --- p.19 / Chapter Chapter 2 --- Instrumentation --- p.23 / Chapter 2.1 --- Introduction --- p.23 / Chapter 2.2 --- Atomic Force Microscopy --- p.23 / Chapter 2.2.1 --- Principle of Atomic Force Microscopy --- p.24 / Chapter 2.2.2 --- Instrumentation --- p.29 / Chapter 2.3 --- Absorption and Fluorescence spectroscopy --- p.30 / Chapter 2.3.1 --- Basic Principle --- p.30 / Chapter 2.3.2 --- Instrumentation --- p.33 / Chapter 2.4 --- I-V characteristic --- p.36 / Chapter 2.4.1 --- Basic principle --- p.36 / Chapter 2.4.2 --- Instrumentation --- p.36 / Chapter 2.5 --- Other instrumentations --- p.37 / References --- p.38 / Chapter Chapter 3 --- Preparation of DNA/QD network systems --- p.39 / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- Preparation of DNA/QD network conjugates in solution --- p.39 / Chapter 3.2.1 --- Experimental --- p.39 / Chapter 3.2.2 --- Characterization --- p.41 / Chapter 3.3 --- Preparation of DNA/QD network on substrates --- p.44 / Chapter 3.3.1 --- Experimental --- p.44 / Chapter 3.3.2 --- Characterization --- p.46 / Chapter 3.4 --- Summary --- p.49 / References --- p.50 / Chapter Chapter 4 --- Fluorescence and I-V characteristics for DNA/QD systems --- p.51 / Chapter 4.1 --- Introduction --- p.51 / Chapter 4.2 --- Experimental --- p.52 / Chapter 4.2.1 --- Patterned Au electrodes --- p.52 / Chapter 4.2.2 --- Electric field induced assembly --- p.52 / Chapter 4.3 --- Results and Discussion --- p.55 / Chapter 4.3.1 --- Optical studies of DNA/QD systems --- p.55 / Chapter 4.3.1.1 --- Optical characteristics of QDs used --- p.55 / Chapter 4.3.1.2 --- Optical studies of DNA/QD network systems in solution --- p.56 / Chapter 4.3.1.3 --- Optical studies of DNA cross-linked QD monolayer on substrates --- p.58 / Chapter 4.3.2 --- PV characteristics --- p.62 / Chapter 4.4 --- Summary --- p.64 / References --- p.66 / Chapter Chapter 5 --- DNA-quantum dot molecular opto-electronic switch with combined Forster resonance energy transfer and photovoltaic effect --- p.68 / Chapter 5.1 --- Introduction --- p.68 / Chapter 5.2 --- Experimental --- p.69 / Chapter 5.2.1 --- Preparation of DNA/QD molecular switch in solution --- p.69 / Chapter 5.2.2 --- Preparation of platform of molecular optoelectronic switch --- p.72 / Chapter 5.2.3 --- EFIA --- p.73 / Chapter 5.3 --- Results and Discussion --- p.73 / Chapter 5.3.1 --- Optical studies of molecular switch constructed of DNA/QD/Cy5 system --- p.73 / Chapter 5.3.1.1 --- Studies on optical properties of molecular switch as well as sole FRET effect between QD and Cy5in solution --- p.73 / Chapter 5.3.1.2 --- Optical studies of dsDNAs cross-linked QD monolayer on substrates with presence of Cy5 --- p.79 / Chapter 5.3.2 --- Studies on FRET mediated PV effect of DNA/QD/Cy5 molecular optoelectronic switch --- p.80 / Chapter 5.4 --- Summary --- p.82 / References --- p.83 / Chapter Chapter 6 --- Conclusions and Future Work --- p.84 / Chapter 6.1 --- Conclusions --- p.84 / Chapter 6.2 --- Future work --- p.85

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

published_or_final_version / Statistics and Actuarial Science / Doctoral / Doctor of Philosophy