GENETIC VARIATION, LOCAL ADAPTATION AND POPULATION STRUCTURE IN NORTH AMERICAN RED OAK SPECIES, QUERCUS RUBRA L. AND Q. ELLIPSOIDALIS E. J. HILL

Forest trees, like oaks, rely on high levels of genetic variation to adapt to varying environmental conditions. Thus, genetic variation and its distribution are important for the long-term survival and adaptability of oak populations. Climate change is projected to lead to increased drought and fire events as well as a northward migration of tree species, including oaks. Additionally, decline in oak regeneration has become increasingly concerning since it may lead to decreased gene flow and increased inbreeding levels. This will in turn lead to lowered levels of genetic diversity, negatively affecting the growth and survival of populations. At the same time, populations at the species’ distribution edge, like those in this study, could possess important stores of genetic diversity and adaptive potential, while also being vulnerable to climatic or anthropogenic changes. A survey of the level and distribution of genetic variation and identification of potentially adaptive genes is needed since adaptive genetic variation is essential for their long-term survival. Oaks possess a remarkable characteristic in that they maintain their species identity and specific environmental adaptations despite their propensity to hybridize. Thus, in the face of interspecific gene flow, some areas of the genome remain differentiated due to selection. This characteristic allows the study of local environmental adaptation through genetic variation analyses. Furthermore, using genic markers with known putative functions makes it possible to link those differentiated markers to potential adaptive traits (e.g., flowering time, drought stress tolerance). Demographic processes like gene flow and genetic drift also play an important role in how genes (including adaptive genes) are maintained or spread. These processes are influenced by disturbances, both natural and anthropogenic. An examination of how genetic variation is geographically distributed can display how these genetic processes and geographical disturbances influence genetic variation patterns. For example, the spatial clustering of closely related trees could promote inbreeding with associated negative effects (inbreeding depression), if gene flow is limited. In turn this can have negative consequences for a species’ ability to adapt to changing environmental conditions. In contrast, interspecific hybridization may also allow the transfer of genes between species that increase their adaptive potential in a changing environment. I have studied the ecologically divergent, interfertile red oaks, Quercus rubra and Q. ellipsoidalis, to identify genes with potential roles in adaptation to abiotic stress through traits such as drought tolerance and flowering time, and to assess the level and distribution of genetic variation. I found evidence for moderate gene flow between the two species and low interspecific genetic differences at most genetic markers (Lind and Gailing 2013). However, the screening of genic markers with potential roles in phenology and drought tolerance led to the identification of a CONSTANS-like (COL) gene, a candidate gene for flowering time and growth. This marker, located in the coding region of the gene, was highly differentiated between the two species in multiple geographical areas, despite interspecific gene flow, and may play a role in reproductive isolation and adaptive divergence between the two species (Lind-Riehl et al. 2014). Since climate change could result in a northward migration of trees species like oaks, this gene could be important in maintaining species identity despite increased contact zones between species (e.g., increased gene flow). Finally I examined differences in spatial genetic structure (SGS) and genetic variation between species and populations subjected to different management strategies and natural disturbances. Diverse management activities combined with various natural disturbances as well as species specific life history traits influenced SGS patterns and inbreeding levels (Lind-Riehl and Gailing submitted).

HOG CHAINS AND MARK TWAINS: A STUDY OF LABOR HISTORY, ARCHAEOLOGY, AND INDUSTRIAL ETHNOGRAPHY OF THE STEAMBOAT ERA OF THE MONONGAHELA VALLEY 1811-1950

This dissertation examines a unique working class in the United States, the men and women who worked on the steamboats from the Industrial Revolution until the demise of steam-powered boats in the mid-20th century. The steamboat was the beginning of a technological system that was developed in America and used in such great numbers that it made the rapid population of the Trans-Appalachian West possible. The steamboat was forever romanticized by images of the antebellum South or the quick wit of Samuel Clemens and his sentimental book, Life on the Mississippi. The imagination swirls with thoughts of boats, bleach white, slowly churning the calm waters of some Spanish moss covered river. The reality of the boats and the experience of those who worked on them has been lost in this nostalgic vision. This research details the history of the western steamboat in the Monongahela Valley, the birthplace of the commercial steamboat industry. The first part of this dissertation examines the literature of authors in the field of labor history and Industrial Archaeology to place this work into the larger context of published literature. The second builds a framework for understanding the various eras that the steamboat went through both in terms of technological change, but also the change the workers experienced as their identity as a working class was being shaped. The third part details the excavations of two steamboat captains houses, those of Captain James Gormley and Captain Michael A. Cox. Both men represented a time in which the steamboat was in an era of transition. Excavations at their homes yield clues to their class status and how integrated they were in the local community. The fourth part of this study documents the oral histories of steamboat workers, both men and women, and their experience on the boats and on the river. Their rapidly declining population of those who lived and worked on the boats gives urgency for their lives to be documented. Finally, this study concludes with a synthesis of how worker identity solidified in the face of technological, socio-economic, and ideological change especially during their push for unionization and the introduction of the diesel towboat.