🔬 BLAST Search
This tool performs a BLASTN (Basic Local Alignment Search Tool) search. It takes a single nucleotide sequence and compares it against a database to find regions of local similarity. The results are displayed as cards, showing the most significant matches, their E-values, identity percentages, and genomic coordinates.
1. Query and Actions
Query Input
The large text area is dedicated to receiving the query sequence.
| Input Type | Requirement | Description |
|---|---|---|
| Query Sequence | Single nucleotide (DNA) sequence. | The sequence must be provided in raw text format (not FASTA, though the example implies raw sequence data). |
Action Buttons
| Button | Function |
|---|---|
| Run BLAST | Initiates the search process using the query sequence against the configured database. |
| Clear | Clears the text editor of the query sequence. |
| Example | Pre-fills the input box with a sample query sequence for quick testing. |
2. Filter & Sort Controls
After the BLAST search is complete, users can refine the displayed results using the controls provided below the input area.
| Control | Type | Description |
|---|---|---|
| Max E-value | Dropdown/Input | Sets the maximum acceptable Expectation Value (E-value) for a result to be shown. Lower E-values indicate higher reliability. |
| Min Identity (%) | Dropdown/Input | Sets the minimum required percentage of identical residues between the query and the matched sequence. |
| Source | Dropdown | Filters results based on the original data source of the matching sequence (e.g., specific genome assembly or annotation project). |
| Organism | Dropdown | Filters results to only show matches against a selected organism. |
| Sort By | Dropdown | Allows the user to order the result cards by different metrics (e.g., E-value, Identity, Location). |
| Reset | Button | Clears all active filters and sorting options, returning the view to the default result set. |
3. Search Result Cards
Each card represents a significant match (a "Hit") found by the BLAST algorithm.
Key Match Statistics
The header of each card displays the most important statistics for the match:
- Organism: The species of the matching sequence.
- Tax ID: The NCBI Taxonomy ID for the organism.
- E-value: The probability due to chance that there is another alignment score as good as or better than the score given. Lower is better.
- Identity (%): The percentage of residues that are identical between the query and the hit in the aligned region.
- Visual Identity Bar: A colored bar that visually represents the identity percentage.
Genomic Location
- Location: The chromosomal coordinates of the matching sequence within its organism's genome (e.g.,
Chr01: 11065053 - 11065160). - Assembly: The specific assembly version the sequence belongs to.
- Source: The project or database the sequence was derived from (e.g.,
SUN_X2,PhytoZyme).