Rationalizing the Ratio Difference: Analysis of Molecular Factors Related to Primate Skeletal Muscle Fiber Type
| dc.contributor.author | Lewis, Franklin Scott | |
| dc.date.accessioned | 2019-11-07T16:12:58Z | |
| dc.date.available | 2019-11-07T16:12:58Z | |
| dc.date.issued | 2019 | |
| dc.description | 56 pages | |
| dc.description.abstract | Bipedalism is a defining human characteristic. Most research on human bipedal evolution has focused on the origins of bipedalism using fossil evidence and bone morphology analysis. Yet few studies have investigated the maximization of bipedal locomotion. In particular, little is known as to how muscular changes influenced human bipedal evolution. In skeletal muscle, slow-twitch fibers produce energy more efficiently and are better suited for endurance activities, whereas fast-twitch fibers consume more energy and are advantageous for activities requiring short bursts of power. When compared to their closest living relatives, the skeletal muscles of bipedal humans have more slow-twitch fibers than those of the quadrupedal apes, but it is still unclear how evolution shaped these patterns. My research addresses this gap in knowledge by characterizing a set of candidate genes that encode proteins that play a role in skeletal muscle physiology and the development of skeletal muscle fiber type. First, I compared the protein-coding sequences of four candidate genes in 25 primates to test if these genes evolved under positive selection. Second, I tested if these genes were differentially expressed in the skeletal muscle tissue of primates with different locomotor strategies (i.e., quadrupeds and bipeds). The structure of each skeletal muscle fiber is generally conserved between species, whereas the abundance ratio is not. Because genes sequences typically specify the structure of proteins, and the expression of genes specific protein abundance, I predicted that differential gene expression, rather than changes in the coding sequences of genes, is the main source of variation in skeletal muscle fiber-type ratios across species. Preliminary data suggest that these genes are highly conserved across primates and that the expression of these genes in human skeletal muscle tissue is similar to that of other primates. However, I found 2,426 genes that were differentially expressed between human and non-human primates. Reconstructing the evolutionary history of this trait is important for understanding the evolution of human bipedalism and identifying genes involved in skeletal muscle fiber type may also inform our understanding of neuromuscular diseases. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/25039 | |
| dc.language.iso | en_US | |
| dc.publisher | University of Oregon | |
| dc.rights | Creative Commons BY-NC-ND 4.0-US | |
| dc.subject | Biology | en_US |
| dc.subject | Bipedal Evolution | en_US |
| dc.subject | Muscle Fiber | en_US |
| dc.subject | Slow Twitch | en_US |
| dc.subject | Genetic Variation | en_US |
| dc.subject | Differential Expression | en_US |
| dc.title | Rationalizing the Ratio Difference: Analysis of Molecular Factors Related to Primate Skeletal Muscle Fiber Type | |
| dc.type | Thesis/Dissertation |
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