BLAST graphics
The BLAST
editor shows the sequences hits which were found in the BLAST
search. The hit sequences are represented by colored horizontal
lines, and when hovering the mouse pointer over a BLAST hit
sequence, a tooltip appears, listing the characteristics of the
sequence. As default, the query sequence is fitted to the window
width, but it is possible to zoom in the windows and see the actual
sequence alignments returned from the BLAST server.
There are several settings available in the BLAST Settings side panel.
- Compactness. You can control the level of sequence detail to be displayed:
- Not compact. Full detail and spaces between the sequences.
- Low. The normal settings where the residues are visible (when zoomed in) but with no extra spaces between.
- Medium. The sequences are represented as lines and the residues are not visible. There is some space between the sequences.
- Compact. Even less space between the sequences.
- BLAST layout. You can choose to Gather sequences at top. Enabling this option affects the view that is shown when scrolling horizontally along a BLAST result. If selected, the sequence hits which did not contribute to the visible part of the BLAST graphics will be omitted whereas the found BLAST hits will automatically be placed right below the query sequence.
- BLAST hit coloring. You can choose whether to color hit sequences and adjust the coloring scale for visualisation of identity level.
The remaining View preferences for BLAST Graphics are the same as those of alignments. See section View sequence.
Some of the information available in the tooltips is:
- Name of sequence. Here is shown some additional information of the sequence which was found. This line corresponds to the description line in GenBank (if the search was conducted on the nr database).
- Score. This shows the bit score of the local alignment generated through the BLAST search.
- Expect. Also known as the E-value. A low value indicates a homologous sequence. Higher E-values indicate that BLAST found a less homologous sequence.
- Identities. This number shows the number of identical residues or nucleotides in the obtained alignment.
- Gaps. This number shows whether the alignment has gaps or not.
- Strand. This is only valid for nucleotide sequences and show the direction of the aligned strands. Minus indicate a complementary strand.
The numbers of the query and subject sequences refer to the sequence positions in the submitted and found sequences. If the subject sequence has number 59 in front of the sequence, this means that 58 residues are found upstream of this position, but these are not included in the alignment.
By right clicking the sequence name in the Graphical BLAST output it is possible to download the full hits sequence from NCBI with accompanying annotations and information. It is also possible to just open the actual hit sequence in a new view.