Ricerc@Sapienza

A phylogenetic tree is a structure showing the evolutionary relationships among various biological species or other entities (taxa), their phylogeny, based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry, called the Tree of Life.

Several automatic procedures have been designed to produce the phylogenetic tree for a group of species; all of them work on the basis of partial information and complete it using different optimality criteria. Changing the tool or the optimality criteria different trees are produced.
Comparing these trees to find their similarities and dissimilarities (and looking among them for the most probable one) is an important issue in biology.

In the literature, there is plenty of definitions of possible distance metrics that have been proposed to compare phylogenetic trees and extensively studied, but most of them seem to be completely uncorrelated each other.

Moreover, the evolutionary development of more organisms at the same time (e.g. of symbionts) is studied by co-phylogeny and, in order to do this, two or more phylogenetic trees are compared to detect possible evolutive similarities.
So, one of the main issues in this context consists again in comparing trees.

In this research, we will compare different measures of similarity for trees, in order to understand on the one hand if there are connections and correlations, on the other hand if some of them are more suitable than other to extract some biological information about evolution and co-evolution.

Finally, we will deep inside the important concept of reconciliation (that can be seen in some sense as a distance for trees), in order to understand whether it is possible to exploit it to deduce again information about co-evolution.