Copy of previously published article by author, inserted. / Bibliography: leaves 217-233. / xix, 233 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The rDNA work presented aimed to determine if B chromosome sequences of Brachycome dichromosomatica were transcriptionally active. / Thesis (Ph.D.)--University of Adelaide, Dept. of Genetics, 1999

Thesis (Ph.D.)--Montana State University--Bozeman, 2006. / Typescript. Chairperson, Graduate Committee: Janice Bowman. Includes bibliographical references.

No description available.

Culex tarsalis is a major vector of West Nile Virus (WNV) in North America. Although the genome for this species was recently sequenced, the physical genome map has not developed. Unlike other Culex species, that have sex-determination locus on chromosome 1, the sex locus in Cx. tarsalis is located on chromosome 3, the longest chromosome. It is currently unknown if this difference is associated with chromosomal rearrangements. The objectives of this study were to develop a high-resolution map for the precise physical genome mapping in Cx. tarsalis and to compare mitotic chromosomes between three species of Culicinae mosquitoes. Using mitotic chromosomes from imaginal discs of 4th instar larvae of Cx. tarsalis, we developed idiograms based on morphology and proportions of the mitotic chromosomes. In addition, the physical mapping of ribosomal genes using fluorescence in situ hybridization was performed. The comparative analysis of Cx. tarsalis to Cx. pipiens and Cx. quinquefasciatus chromosomes showed that the total chromosome length in Cx. tarsalis is longer than the other two species suggesting the bigger genome size in this mosquito. A comparison of the relative chromosome length between the species indicated no significant differences suggesting that no large chromosomal translocation occurred between the species. Comparisons of the centromeric indexes demonstrated a significant difference in chromosome 1 between Cx. pipiens and Cx. quinquefasciatus. This difference suggests the presence of pericentric inversion between the species or amplification of ribosomal genes in Cx. pipiens. Studying mosquito chromosomes advances our understanding of Culex cytogenetics. Further comparative physical mapping of the three major mosquito genera will help us to understand the evolution of genus Culex better and to develop genome-based strategies for the vector control. / Master of Science in Life Sciences / West Nile Virus (WNV) is the most common virus transmitted to humans by mosquitoes in the United States. While many species of mosquitoes are known to carry WNV, Culex tarsalis is a major vector on the west coast of North America. However, previous research on Cx. tarsalis lack chromosome studies on this mosquito. Our study aims to develop a high-quality chromosome map for Cx. tarsalis and to compare the mitotic chromosomes of Cx. tarsalis and Cx. quinquefasciatus and Cx. pipiens in respect of chromosomal rearrangements. We used a fluorescent DNA probe to find the location of the ribosomal locus in the chromosomes of Cx. tarsalis. This study developed a cytogenetic tool for further genomic studies of Cx. tarsalis that will help to develop genome-based strategies for vector control. Comparing the physical mapping of the three major mosquito genera will help to understand the genome evolution in Culicinae mosquitoes better.

Not available / text

No description available.

No description available.

Chicken genomic DNA containing 5 kb of the 5$ sp prime$ end of the growth hormone (GH) receptor gene and 12 kb of the region up-stream was cloned and a restriction map was constructed. Using subcloned fragments as probes, a HindIII polymorphism was detected in both egg layer and in meat-type chickens. This polymorphic site was mapped at 7 kb up-stream of the coding region of the GH-receptor gene and a PCR assay for the polymorphism was developed to facilitate genotyping of large numbers of chickens. / Alleles of the GH-receptor gene and the GH gene were analyzed for association with traits in chicken strains of different genetic origins. In egg layers, association was significant for juvenile body weight, egg weight, feed consumption and feed efficiency for egg mass (P $<$ 0.05). In meat-type chickens, the GH-receptor allele associated with high juvenile body weight in egg layers was co-selected with leanness. A comparison of the genotype classes revealed that for several traits there was significant interaction between the GH and GH-receptor genotype. The results indicated that there are variants of the genes of the GH-axis which affect traits in White Leghorns and that the effect of a genetic variation in one gene may depend on the variation in another gene.

We assembled the genome of the human fungal pathogen Candida albicans into eight chromosomes, and annotated each of its genes. A genome comparison with Saccharomyces cerevisiae revealed an increased number of C. albicans superoxide dismutase genes. We analyzed the expression patterns and the function of one of these genes, SOD5, whose role is to protect the pathogen against extracellularly produced, neutrophil-generated superoxide radicals. Comparative genomics also showed that although many of the C. albicans transcription factors, such as Gal4p and Gcn4p, have homologues in S. cerevisiae, the sequence similarities occur only in the DNA binding motifs of those proteins. Deletion analysis of CaGcn4 and CaGal4 proteins show that the N' and C' termini respectively are needed for their transactivation ability. These two transactivation regions show no sequence similarity to the equivalent domains in their S. cerevisiae homologues, and the two C. albicans transactivatiog domains themselves show little similarity. A comparative analysis of the transcriptional machinery between C. albicans and S. cerevisiae showed low sequence similarity of the mediator complex that bridges activation domains of transcription factors to the RNA polymerase II complex. We performed a comparison of intergenic DNA regions to identify the cis-regulatory elements from Candida and Saccharomyces species to examine the organization of the transcriptional regulatory networks between these two organisms. We observed that the C. albicans GAL genes lack Gal4p binding sites, but that such sites are found upstream of telomeric genes and genes involved in glycolysis, and we show that CaGal4p regulates the expression of those genes. We identified the regulatory DNA sequences in the promoters of GAL genes, including a GAL-specific palindrome necessary for GAL10&ogon; expression. Cph1p, the C. albicans homolog of the Ste12p transcription factor controlling pheromone-induced gene expression in yeast, acts through this GAL-specific palindrome, functioning as an activator in the presence of galactose. This shows C. albicans and S. cerevisiae can regulate the same process by different regulatory circuits.

DNA markers tightly-linked to nuclear fertility restorer genes for cytoplasmic male sterility (CMS) are valuable tools for breeders and researchers working with these genes. Two different targeting approaches were used to identify markers linked to the Rfp1 restorer gene for the pol CMS of canola (Brassica napus L.): nearly isogenic line (NIL) comparison and bulked segregant analysis. These methods were equally efficient in identifying markers linked to Rfp1; combining them allowed a targeting efficiency of 100% to be achieved. The efficiency of bulked segregant analysis was found to be limited by the inadvertent occurrence of shared homozygosity at specific chromosomal regions in the bulks, in contrast with the efficiency of NIL comparison which was limited by the occurrence of residual DNA from the donor cultivar at scattered sites around the genome of the NILs. Eleven DNA markers linked to the Rfp1 gene were identified, one of which perfectly co-segregates with Rfp1. The linkage group on which Rfp1 is localized contains 17 DNA markers. Two restorer genes of the pol CMS, Rfp1 and Rfp2, and a Rfn restorer gene of the nap CMS were found to be at least tightly linked to one another and may all reside at the same locus. A fourth restorer gene, the Rfo restorer for the ogu CMS, was, however, found to be unlinked to the other restorer genes. Different restorer genes for the nap CMS were found in the lines 'Westar-Rf and 'Karat'. A linkage map of the B. napus genome containing 146 markers organized into 23 linkage groups covering a total length of 850.2 cM was constructed from a BC$ sb1$ population. This map contains 63 loci previously localized on the B. napus genome through analysis of an F$ sb2$ population. Comparative analysis indicates that the total length of the BC$ sb1$-derived map is smaller than that of the F$ sb2$-derived map, which suggests that a reduction in recombination frequency is occurring in male gametes. The preferential use of two or three probe-