Scientists use phylogenetic trees to show how different species are related through evolution. The Billera-Holmes-Vogtmann (BHV) space is a framework that helps compare these trees, however, trees cannot be compared using BHV space if they don’t have the same set of species.
To solve this limitation, University of Washington postdoctoral researcher María A. Valdez-Cabrera, PhD '24, and faculty member Amy Willis created the Towering space. Towering space organizes BHV spaces into a nested hierarchy, where transitions between BHV spaces are possible by removing or adding leaves to the trees.
Their approach can be used to study the evolutionary history of genes that are gained and lost by organisms. For example, bacteria gain and lose antibiotic resistance genes as needed, but since not all bacteria have antibiotic resistance genes, tools like Towering space are needed to compare the history of resistance to the history of other genes.
The team’s work appeared in a recent Advances in Applied Mathematics and was supported by NIH NIGMSR35 GM133420and NSF 2415614.
