Event Title

Efficient Quartet Systems: A New Systematic Approach to Supertree Reconstruction

Poster Number

28

Presenter Information

MaLyn Lawhorn, Winthrop University

Faculty Mentor

Joseph Rusinko, Ph.D.

College

College of Arts and Sciences

Department

Mathematics

Location

Richardson Ballroom

Start Date

24-4-2015 3:20 PM

End Date

24-4-2015 4:50 PM

Description

A phylogenetic tree is described by quartets that show where a split in the tree should occur. The number of compatible quartets that define a tree is the number of taxa on the tree to the fourth power. Scientists often want to combine multiple phylogenetic trees, or input trees, to derive a “supertree.” This is typically done by giving a collection of all the quartets that define the input trees to tree reconstruction software such as MaxCut. However, the number of compatible quartets that define a supertree is often too large for MaxCut to handle and contains a lot of conflicting quartets. Therefore, it would be helpful to find a subset of quartets which would return a correct input tree so that, when the quartet systems defining the input trees are combined, there are not too many quartets for MaxCut to consider and a correct supertree is returned. An efficient quartet system is a collection of quartets which distinguish unique paths across a phylogenetic tree. An efficient quartet system is found by first distinguishing each internal vertex on a phylogenetic tree with pairs of taxa and then consistently using these vertex-distinguishing pairs to create quartets that distinguish the paths of the tree. An efficient quartet system reduces the number of quartets used to reconstruct a tree and, additionally, returns the correct tree for multiple different topologies of trees.

Comments

Presented at the MAA Joint Mathematics Meeting, January 2015, and the South Carolina INBRE Spring Symposium, February 2015

Supported by an NIH-INBRE grant from the National Center for Research Resources and the National Institute of General Medical Sciences

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Apr 24th, 3:20 PM Apr 24th, 4:50 PM

Efficient Quartet Systems: A New Systematic Approach to Supertree Reconstruction

Richardson Ballroom

A phylogenetic tree is described by quartets that show where a split in the tree should occur. The number of compatible quartets that define a tree is the number of taxa on the tree to the fourth power. Scientists often want to combine multiple phylogenetic trees, or input trees, to derive a “supertree.” This is typically done by giving a collection of all the quartets that define the input trees to tree reconstruction software such as MaxCut. However, the number of compatible quartets that define a supertree is often too large for MaxCut to handle and contains a lot of conflicting quartets. Therefore, it would be helpful to find a subset of quartets which would return a correct input tree so that, when the quartet systems defining the input trees are combined, there are not too many quartets for MaxCut to consider and a correct supertree is returned. An efficient quartet system is a collection of quartets which distinguish unique paths across a phylogenetic tree. An efficient quartet system is found by first distinguishing each internal vertex on a phylogenetic tree with pairs of taxa and then consistently using these vertex-distinguishing pairs to create quartets that distinguish the paths of the tree. An efficient quartet system reduces the number of quartets used to reconstruct a tree and, additionally, returns the correct tree for multiple different topologies of trees.