系統発生学および進化生物学ジャーナル

How Much Morphological Support is Needed to Change a Phylogenomic Based Recalcitrant Node?

Abstract

Rob DeSalle*

In this paper we examine the relative contribution of information to nodes in a phylogenomic analysis combined with a morphological dataset. We examine the behavior of branch support metrics using the partitioned Bremer support or PBS. This metric measure the contribution of a data partition to a node in question and can be easily computed for likelihood (PLS) and parsimony (PBS). In addition, we use an artificial metric associated with phylogenomic matrices that is similar to branch support that we call the “flip weight”. When two competing and incongruent partitions are analyzed the flip weight is the weight of the weaker partition that results in a change in topology in a concatenated analysis. To quantitate our observations about PBS, PLS and flip weight we use a specific case of a recalcitrant node in phylogenomic analysis – the sister of all other metazoans (SOM). Specifically, we assess the ratio of PBS/PLS values of molecular to morphological support at this recalcitrant node in comparison to flip weight. We find that there is a strong correlation between the PBS/PLS ratio with the weight of the weaker partition where a flip in topology ensues. We use this correlation to calibrate the flip weight for competing partitions at a recalcitrant node.