All ETDs from UAB

Advisory Committee Chair

Scott W Ballinger

Advisory Committee Members

Robert U Fischer

Mark D Garfinkel

Document Type

Thesis

Date of Award

2010

Degree Name by School

Master of Science (MS) College of Arts and Sciences

Abstract

Recently, it has been suggested that differences in mitochondrial function enabled Homo sapiens to migrate out of Africa by enabling humans to adapt to colder environments as they migrated to higher latitude areas. Through mitochondrial mutations that partially uncoupled oxidative phosphorylation, humans that moved to colder areas were able to generate more heat for better survival, while producing less energy. However, due to challenges in working with human populations, no specific studies have been able to show the existence of such differences in mitochondrial function within healthy humans. Because of numerous advantages of Drosophila as a developmental model, such as short generation, large population size, wide availability, cost effectiveness, and well established knowledge base, the study compared aspects of mitochondrial functions of Drosophila, specifically, species that originated from different latitudes. The results from the study revealed three main points. First, it was observed that Drosophila ananassae is a warm, tropical species and Drosophila subobscura is a cold-tolerant species. Secondly, the results of the study showed significant differences in O2 utilization between Drosophila ananassae and Drosophila subobscura. The maximum oxygen consumption was significantly higher in D. ananassae than D. subobscura. However, D. subobscura consumed more oxygen for non-ATP than D. ananassae. Thus, the mitochondria of D. subobscura were found to be less efficient (more loosely coupled) than D. ananassae and that D. subobscura consumes more calories to generate same amount of energy as D. ananassae. And if the caloric intake of both species is restricted, D. subobscura was anticipated to have shorter survival hours than D. ananassae. Furthermore, D. ananassae showed higher cytochrome c oxidase activity than D. subobscura. Lastly, the mortality rate of Drosophila subobscura was considerably higher than Drosophila ananassae as expected under starvation. While 21.7 deaths occurred in 24 hours in D. subobscura, 16.2 deaths occurred in 24 hours in D. ananassae.

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