Collapsed Tree

In studying the relationship between species trees, which represent the relationships among species, and gene trees, which represent the descent of gene lineages for individual members of those species, to assist with the comparisons, Rosenberg (2002) defined the concept of a collapsed tree. A gene tree with multiple members collected in each of the species is mapped to a "collapsed tree" that provides a summary of the gene tree. The collapsed gene tree is built by examining the most recent gene lineage coalescences for pairs of species, proceeding from the leaves toward the root of the gene tree in adding nodes to the collapsed tree. The idea of the collapsed gene tree features prominently in the GLASS algorithm of Mossel & Roch (2010) for inference of species trees from gene trees.

Photo: Noah Rosenberg, March 23, 2019