Tag Archives: alignment

(re)Annotating GenBank

NCBI LogoTom Bruns, Martin Bidartondo and 250 others sent a letter to Science describing the current problems with fixing annotation in GenBank. There is an entertaining accompanying news article that interviews several people about the problem of updating annotation and species assigned to sequences in the database. In particular the problem for mycologists that many fungi found from metagenomic approaches are only identified through molecular sequences and having the wrong species associated with a sequence can be difficult when studying community ecology composition.  This problem is not limited to fungi by any means, but recent reports find as many as 20% of fungal Intergenic Spacer (ITS) sequences are mis-attributed to the wrong species. 

There’s a nice quote in the news article from Steven Salzberg talking about the difficulties in getting sequences, especially from big centers, updated. I’m sure he is thinking of many examples, like reclassifying some Drosophila sequence traces.

Continue reading (re)Annotating GenBank

New Saccharomyces resequencing assembly

SGRP LogoDavid Carter at the Sanger Centre emailed a message that new assemblies of Saccharomyces strain resequencing project have been posted including a new three-way alignment of S. bayanusS.paradoxusS.cerevisiae. This updates the Dec 2007 release.

Continue reading New Saccharomyces resequencing assembly

Taking into account alignment uncertainty

WrightFisher talks about a paper & the commentary in Science describing how alignment uncertainty should be taken into account when doing phylogenetic analyses on genomic datastets (some might call this phylogenomics, but Dr Eisen won’t). If the sequence alignment is treated as a random variable (and in bayesian approaches have a prior based on result(s) from an alignment program) then more accurate reconstruction. Robin points out several statistical alignment approaches that do just this including TKF91 and recent work that unifies a probabilistic framework with transducers.