2011 Student Research Conference:
24th Annual Student Research Conference

Discerning the Affects of Natural Selection and Genetic Drift by Using a Modification of Tajima's D
Nathan D. Kopp* and Colin D. Teberg
Dr. Anton Weisstein and Mr. Pamela J. Ryan, Faculty Mentors

Many statistical measures have been applied to genetic sequences to discern evolutionary history. One commonly used statistic, Tajimas D, can detect changes in genetic variation; however, it is unable to separate the effects of genetic drift from those of natural selection. We are enhancing Tajimas D by separately applying it to synonymous (DSYN) and nonsynonymous (DNON) mutations. In principle, DSYN will reveal changes in diversity due to drift, while DNON DSYN will indicate the effects of selection. To test this hypothesis, we wrote a computer simulation to model the molecular evolution of HIV under a neutral model: this acted as our null hypothesis. We also used the simulation to model a variety of specific evolutionary scenarios and assessed our models ability to correctly infer evolutionary history. Finally, we tested actual HIV sequence data to the distributions obtained from our simulations. Our results suggest that the modified version of Tajimas test has fairly low statistical power, but can nevertheless correctly distinguish among several major evolutionary models.

Keywords: Tajima's D, genetic variation, synonymous mutations, nonsynonymous mutations, natural selection, genetic drift, statistical power, evolutionary history

Topic(s):Mathematical Biology

Presentation Type: Oral Paper

Session: 32-4
Location: MG 1000
Time: 2:00

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