2006 Student Research Conference:

19th Annual Student Research Conference

19th Annual Student Research Conference

**The Mathematics of Phylogenetic Trees**

Kimberly M. Getman

Mr. Pamela J. Ryan, Faculty Mentor

Evolutionary biology is the aspect of biology that deals with trying to determine how species are related. In order to illustrate the evolutionary relationships between species that allegedly descended from a common ancestor, biologists use a diagram called a phylogenetic tree. Mathematics plays a large role in constructing these trees. One set of approaches used to produce phylogenetic trees are the distance-based methods, which are based on the genetic distance between the species. One prominent distance-based method is the neighbor-joining method, which measures closeness by minimizing the total length of all the branches on a tree. This method involves exploring a formula derived by N. Saitou and M. Nei, as well as using the least-squares estimation of branch lengths. We will explore an example of constructing a tree using this method and look at the mathematics behind this approach.

**Keywords:** phylogenetic trees, neighbor-joining, mathematics, biology

**Topic(s):**Mathematical Biology

**Presentation Type:** Oral Paper

**Session:** 39-1

**Location:** OP 2111

**Time:** 1:15