Questions tagged [blast]

The Basic Local Alignment Search Tool is a widely-used tool for finding and evaluating DNA or protein sequences. Users can utilize either their own sequences or the genomes of hundreds of organisms. It can be found at http://blast.ncbi.nlm.nih.gov/Blast.cgi

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What direction is a sequence in databases written?

In many databases, the DNA sequences for proteins are given as a string of a,t,g,c without specifying whether the starting is from 5' or from 3'. Also it is not specified if it is the coding or non ...
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Scoring matrices (BLOSUM & PAM) in BLAST and other sequence-comparison programs

The Wikipedia page on BLAST states that: The scores are created by comparing the word in the list in step 2* with all the 3-letter words. By using the scoring matrix (substitution matrix) to score ...
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966 views

Local BLAST Copy Number per Hit

I generated a series of local BLAST databases using makeblastdb of metagenomic data and am searching for the presence of a particular gene. While I can do the normal BLAST analysis looking at e-values,...
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2answers
334 views

How do you find pre-miRNAs from mature miRNA Blast output?

So in short, I did a blastn with standalone blast using all known miRNAs against the EST sequences in a genome (word length 7 and e-value 0.01). Now to confirm one of the next steps would be obtain ...
1
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1answer
273 views

How to Determine the Most Conserved Sequence from BLAST Result?

I used BLAST to find the best aligned DNA sequence to my query sequence. The BLAST result shows a number of sequences that it calculated to be the best aligned sequences to the query sequence that I ...