Thesis (M.S.)--University of North Carolina at Greensboro, 2005. / Title from PDF title page screen. Advisor: David L. Remington; submitted to the Dept. of Biology. Includes bibliographical references (p. 51-55).

Thesis (Ph. D.)--Florida State University, 2005. / Advisor: W. Ross Ellington, Florida State University, College of Arts and Sciences, Dept. of Biological Science. Title and description from dissertation home page (viewed Jan. 26, 2006). Document formatted into pages; contains x, 82 pages. Includes bibliographical references.

Thesis (Ph. D.)--Murdoch University, 2005. / Title from PDF title page (viewed on Sept. 24, 2005). Includes bibliographical references (p. 104-120).

Thesis (Ph. D.)--University of Chicago, Committee on Deveopmental Biology, August 2002. / Includes bibliographical references. Also available on the Internet.

Thesis (M.S.)--University of North Carolina at Greensboro, 2005. / Advisor: David L. Remington; submitted to the Dept. of Biology. Includes bibliographical references (p. 51-55).

Extravagant male plumage traits in birds are a classic example of sexual selection. However we know very little about the units that selection is acting upon, the genes themselves – what are they and how are they influenced by sexual selection? In this study I focused on in the evolution and genetics of colouration the galliform birds. Several novel loci were used to create a well resolved phylogeny of this group. This was then used to investigate and reconstruct the evolution of sexual plumage dichromatism. Four pigmentation genes were sequenced in an array of galliform species. A measure of the rate of evolutionary change (dN/dS) at these loci was then compared between lineages with different strengths of sexual selection, using sexual dichromatism as the main index of sexual selection. I found evidence for sexual selection acting at the MC1R locus, in the form of a robust correlation between dN/dS and sexual plumage dichromatism that was not found at any of the other loci. I then went on to investigate the evolution and population genetics of MC1R in the grouse, focusing on the strongly dichromatic black grouse and the relatively monochromatic red grouse. I found some evidence for an adaptive change at this locus between these species. Finally I used a candidate gene approach to investigate the role of several genes in avian pigmentation using the Japanese quail (Coturnix japonica) as a model system. I found evidence that the avian agouti gene is involved in dorso-ventral pigmentation patterning and a regulatory mutation at this locus that produces a yellow phenotype. In addition point mutations at MC1R and TYRP1 were found to be responsible for producing pigmentation variants. I then compared the expression of several of these candidate genes in male and female common pheasants (Phasianus colchicus) and found lower TYRP1 expression in males. Knowledge of the genetic basis of secondary sexual traits and the action of sexual selection at this level could have important implications for our understanding of the process of sexual selection as a whole.

published_or_final_version / Microbiology / Master / Master of Philosophy

The present study aimed to gain better insights into the distribution of genomic variation, in the form of single nucleotide polymorphisms, within the human genome.  Using set theory, the average SNP density of the human genome was found to be 2.6 SNPs per kilobase.  This figure decreased with increasing evolutionary depth, i.e. conservation.  The conserved exonic, intronic subsets had a lower SNP density than the conserved intergenic subset, suggesting that the conserved exonic and intronic regions are under similar strengths of selective pressure while conserved intergenic regions are under a comparatively weaker selective pressure.  To better understand allelic differences on protein-DNA interactions, an algorithm was designed that scored the difference in binding site prediction for the alleles of an SNP.  The program created, RegSNP, was demonstrated to be more accurate than existing resources, and gives results that are relevant of SNP within binding sites in the literature. A further aim of the present study was to isolate potential regulatory regions of the GAL gene, that has been linked to diseases such as obesity and depression, and identify polymorphisms that may alter transcription factor binding.  One excellent candidate element was found by comparative genomics, Gal5.1, and confirmed by transgenic analysis as a transcriptional enhancer element.  Gal5.1, contained a single SNP that RegSNP predicted to interrupt a thyroid hormone receptor binding site.  However, using transgenic animal and cell biology techniques it was concluded that thyroid hormone receptor does not directly interact with the Gal5.1 element, suggesting that the Gal5.1 element must work in synergy with the GAL promoter to stimulate transcription.

Electrophoretic variation in 12 proteins encoded by 16 loci was analyzed to compare the genetic relationships of 18 natural populations representing two species of stoneroller minnows, Campostoma anomalum and C. oligolepis. Ten of the loci were monomorphic and fixed for the same allele in all populations of both species. One locus, Mdh-2, was found to separate both species. Mean heterozygosity for both species was 0.072. Estimates of levels of inbreeding indicated this phenomenon is operating in C. anomalum to structure the populations genetically. Mean genic identity (I) between the two species was high, 0.887, indicating the taxa are closely related. Nevertheless, data accumulated point to the conclusion that the two species maintain electrophoretic variation in 12 proteins encoded by 16 loci was analyzed to compare the genetic relationships of 18 natural populations representing two species of stoneroller minnows, Campostoma anomalum and C. oligolepis. Ten of the loci were monomorphic and fixed for the same allele in all populations of both species. One locus, Mdh-2, was found to separate both species. Mean heterozygosity for both species was 0.072. Estimates of levels of inbreeding indicated this phenomenon is operating in C. anomalum to structure the populations genetically. Mean genic identity (I) between the two species was high, 0.887, indicating the taxa are closely related. Nevertheless, data accumulated point to the conclusion that the two species maintain their genetic integrity throughout their ranges. their genetic integrity throughout their ranges.

Phylogenies constructed from skeletal data often contradict those built from genetic data. This study evaluates the phylogenetic utility of adult male, female, and juvenile hominoid cranial bones. First, I used geometric morphometric methods to compare the cranial bone shapes of seven primate genera (Gorilla, Homo, Hylobates, Macaca, Nomascus, Pan, and Pongo). I then coded these shapes as continuous characters and constructed cladograms via parsimony analysis for the adult male, female, and juvenile character matrices. Finally, I evaluated the similarity of these cladograms to one another and to the genetic phylogeny using topological distance software. Cladograms did not differ from one another or the genetic phylogeny less than comparisons of randomly generated trees. These results suggest that cranial shapes are unlikely to provide accurate phylogenetic information, and agree with other analyses of skeletal data that fail to recover the molecular phylogeny (Collard & Wood, 2000, 2001; Springer et al., 2007). / by Thomas A. DiVito, II. / Title of the abstract: The role of ontogeny for reconstructing hominid phylogeny. / Thesis (M.A.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.