Revising the tree of life

Speaker: Leonidas Salichos , Vanderbilt University, Department of Biological Sciences

Date: Friday, January 17, 2014

Time: 9:30 AM to 11:00 AM Note: all times are in the Eastern Time Zone

Refreshments: 9:30 AM

Public: Yes

Location: 32-G449 (Patil/Kiva)

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Host: Manolis Kellis

Contact: derek aylward, 6177154882,

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Reminder Subject: TALK: Leonidas Salichos : Revising the tree of life

To untangle the tree of life, studies have been using a set of phylogenetic tools and practices including the concatenation of multiple genes, the removal of rogue taxon and slowly evolving genes. Phylogenomic analysis of 1,070 orthologues from 23 yeast genomes showed that the absolutely supported phylogeny inferred by concatenation was incongruent with all 1,070 gene trees. Incongruence severity increased for shorter internodes located deeper on the phylogeny, a result we also observed in vertebrate and metazoan phylogenomic data sets. Using newly developed methods based on information theory, we were able to quantify uncertainty and show that, whereas most practices had little or negative impact on the yeast phylogeny, the retention of genes or internodes with high average clade support significantly improved the species tree resolution. These results question the exclusive reliance on concatenation and associated practices, and argue that selecting genes with strong phylogenetic signal while demonstrating the absence of significant incongruence are a sine qua non for accurately reconstructing internodes that formed in deep time. Perhaps most importantly, it will focus the attention of researchers to develop novel phylogenomic approaches and markers to more accurately decipher the most challenging ancient branches of life’s genealogy from the DNA record.

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Created by derek aylward Email at Thursday, January 16, 2014 at 1:20 PM.