Using CHPC resources to calculate chemical similarity of species of tropical trees

By Gordon Younkin

 Department of Biology, University of Utah

We have developed a metric to quantify the similarity of defensive compounds (secondary metabolites) among different species of plants. The goal is to address fundamental questions in the ecology of tropical forests: What is the origin of the extremely high diversity? How is the exceedingly high local diversity maintained? Our hypothesis is that the answers have to do with the interactions of plants with their herbivores, with particular importance ascribed to the chemical defenses of plants. Here, we report on how we used CHPC resources to quantify the chemical similarity among species of plants.

Using ultra performance liquid chromatography-mass spectrometry (UPLC-MS), we examined the chemical profiles of 166 species of Inga, a genus of tropical trees. Among these species, we have recorded nearly 5000 distinct compounds, most of which are of unknown structure. Based on the abundance of these compounds in each species, we can calculate the overall chemical similarity of each species pair. While each individual calculation is not all that resource-intensive, we have multiple individuals for each species for a total of 795 individuals. Pairwise comparisons between all individuals requires 316,410 separate similarity calculations, a task much too large for a desktop computer. We have parallelized these calculations on a CHPC cluster, where the calculations finish in a matter of hours.

System Status

Cluster Utilization