2008 Student Research Conference:
21st Annual Student Research Conference

Distinguishing Between Genetic Drift and Natural Selection Using Tajima's D Statistic
Karen E. O'Connell* and Dianne M. Kopp
Dr. Anton Weisstein and Mr. Pamela J. Ryan, Faculty Mentors

Several statistical measures have been devised to infer past and/or present evolutionary forces from patterns of genetic diversity in sequence data. Tajima’s D detects increases or decreases in overall genetic diversity, but cannot assess the relative contribution of genetic drift vs. natural selection. By applying Tajima’s D analysis separately to synonymous (DSYN) and nonsynonymous (DNON) mutations, we can separate the effects of drift from those of selection. Specifically, DSYN measures the effects of drift within a population, while DNON – DSYN measures the effects of selection. Critical values for DSYN and DNON – DSYN will be generated under a model of neutral evolution. We will then analyze data obtained from computer simulations of specific evolutionary and demographic histories to measure our method’s ability to correctly infer the population’s history. Although our model reflects the details of HIV evolution, we anticipate our extension of Tajima’s analysis will have broad application.

Keywords: Tajima's D, Natural Selection, Genetic Drift, Synonymous Mutation, Nonsynonymous Mutation, Genetic Diversity, Demographic History, D Critical Values


Presentation Type: Oral Paper

Session: 30-5
Location: VH 1432
Time: 2:15

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