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Showing posts with label BLAST. Show all posts
Showing posts with label BLAST. Show all posts

BLAST a sequence and get a tree and a map

I've updated the BLAST a sequence and get a tree tool described in a previous post to output additional details, such as a list of the sequences used to build the tree and some basic metadata (such as the taxon name, name of any associated host, publication, and geographic coordinates). If the sequences are geotagged, then you will also see a little map showing the localities. As ever, all this relies on SVG, so if you're browser doesn't support that out won't see much.

The example below is for the sequence EU399074, which falls in a cluster of "dark taxa"; in this case, DNA barcode sequences that haven't been properly labelled.

Blastmap

BLAST a sequence and get a tree

For this weeks sessions of my phyloinformatics course I'm developing some phylogeny tools. The first is a simple AJAX-based BLAST tool. I've always wanted a quick way to see a GenBank sequence in its phylogenetic context, so I've built a simple tool to that takes a GenBank accession number or GI number, submits a BLAST job, retrieves the sequences, aligns them using CLUSTALW, builds a quick and dirty neighbour-joining tree using PAUP*, then displays the tree using SVG (if your browser doesn't support this you won't see the tree). One use for this is to quikcly get a sense of whether an unnamed ("dark") taxon is related to sequences that have been identified.

Nothing fancy, but it was a chance to display the whole process in the browser without opening new windows or refreshing the page. Here's an example for the GenBank sequence FJ559186:



For the technically-minded, the calls to BLAST and the alignment and tree construction tools all use AJAX, and there's a simple Javascript timer to countdown the seconds that the NCBI BLAST web service estimates the BLAST job will take, before we poll NCBI to see if the job has in fact finished. The code is in GitHub.