phylogeny

Phylogeny

Phylogenetic supertrees

One of the ultimate goals of phylogeny is to assemble the whole tree of life. It is however difficult to find characters allowing comparisons at such a large scale, and to gather data for all species for these few universal characters. A more reasonable approch is to combine the results of phylogenetic studies made at various scales. This problem (combining trees made on various sets of species into a single big tree) is called the supertree problem. During the last ten years, several kinds of methods have been developed for constructing supertrees.

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Date: 
Wed, 06/05/2009 - 12:30
Speaker: 
Blaise Li

A reliability index for clades, based on taxonomical congruence

I will present part of my PhD work in phylogeny. Phylogeneticists use comparative data to reconstruct the "genealogy" of taxa (usually, species or genuses): a "phylogeny". The data can be morphological characters, DNA sequences, etc. A practical problem is that on large groups, different datasets tend to produce trees that are not the same. By comparing trees obtained from different independent datasets, one can get an idea of which clades (groups of taxa) are reliable and which are not. The more a group is repeated, the more it is reliable.

Date: 
Wed, 14/01/2009 - 12:30
Speaker: 
Blaise Li

A stochastic local search algorithm for phylogenetic reconstruction

The reconstruction of the phylogenetic history belongs to a general class of inverse problems whose relevance is now well established in many different disciplines ranging from biology to linguistics and social sciences. In a generic inverse problem one is given with a set of data and one has to infer the most likely dynamical evolution processes that presumably produced the given data set. The problem that all the algorithms for phylogenetic reconstruction have to face is that of the deviations from a purely phylogenetic process.

Date: 
Wed, 08/07/2009 - 12:30
Speaker: 
Francesca Tria
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