blast_nucleotide_to_nucleotide: Perform Nucleotide to Nucleotide BLAST Searches (BLASTN)

In drostlab/metablastr: Perform Massive Local BLAST Searches

Perform Nucleotide to Nucleotide BLAST Searches (BLASTN)

Description

Run nucleotide to nucleotide BLAST of reference sequences against a blast-able database or fasta file.

Usage

blast_nucleotide_to_nucleotide(
  query,
  subject,
  strand = "both",
  output.path = NULL,
  is.subject.db = FALSE,
  task = "blastn",
  db.import = FALSE,
  postgres.user = NULL,
  evalue = 0.001,
  out.format = "csv",
  cores = 1,
  max.target.seqs = 10000L,
  db.soft.mask = FALSE,
  db.hard.mask = FALSE,
  blast.path = NULL
)

Arguments

query	path to input file in fasta format.
subject	path to subject file in fasta format or blast-able database.
strand	Query DNA strand(s) to search against database/subject. Options are: strand = "both" : query against both DNA strands. strand = "minus" : query against minus DNA strand. strand = "plus" : query against plus DNA strand.
output.path	path to folder at which BLAST output table shall be stored. Default is output.path = NULL (hence getwd() is used).
is.subject.db	logical specifying whether or not the subject file is a file in fasta format (is.subject.db = FALSE; default) or a fasta file that was previously converted into a blast-able database using makeblastdb (is.subject.db = TRUE).
task	nucleotide search task option. Options are: task = "blastn" : Standard nucleotide-nucleotide comparisons (default) - Traditional BLASTN requiring an exact match of 11. task = "blastn-short" : Optimized nucleotide-nucleotide comparisons for query sequences shorter than 50 nucleotides. task = "dc-megablast" : Discontiguous megablast used to find somewhat distant sequences. task = "megablast" : Traditional megablast used to find very similar (e.g., intraspecies or closely related species) sequences. task = "rmblastn"
db.import	shall the BLAST output be stored in a PostgresSQL database and shall a connection be established to this database? Default is db.import = FALSE. In case users wish to to only generate a BLAST output file without importing it to the current R session they can specify db.import = NULL.
postgres.user	when db.import = TRUE and out.format = "postgres" is selected, the BLAST output is imported and stored in a PostgresSQL database. In that case, users need to have PostgresSQL installed and initialized on their system. Please consult the Installation Vignette for details.
evalue	Expectation value (E) threshold for saving hits (default: evalue = 0.001).
out.format	a character string specifying the format of the file in which the BLAST results shall be stored. Available options are: out.format = "pair" : Pairwise out.format = "qa.ident" : Query-anchored showing identities out.format = "qa.nonident" : Query-anchored no identities out.format = "fq.ident" : Flat query-anchored showing identities out.format = "fq.nonident" : Flat query-anchored no identities out.format = "xml" : XML out.format = "tab" : Tabular separated file out.format = "tab.comment" : Tabular separated file with comment lines out.format = "ASN.1.text" : Seqalign (Text ASN.1) out.format = "ASN.1.binary" : Seqalign (Binary ASN.1) out.format = "csv" : Comma-separated values out.format = "ASN.1" : BLAST archive (ASN.1) out.format = "json.seq.aln" : Seqalign (JSON) out.format = "json.blast.multi" : Multiple-file BLAST JSON out.format = "xml2.blast.multi" : Multiple-file BLAST XML2 out.format = "json.blast.single" : Single-file BLAST JSON out.format = "xml2.blast.single" : Single-file BLAST XML2 out.format = "SAM" : Sequence Alignment/Map (SAM) out.format = "report" : Organism Report
cores	number of cores for parallel BLAST searches.
max.target.seqs	maximum number of aligned sequences that shall be retained. Please be aware that max.target.seqs selects best hits based on the database entry and not by the best e-value. See details here: https://academic.oup.com/bioinformatics/advance-article/doi/10.1093/bioinformatics/bty833/5106166 .
db.soft.mask	shall low complexity regions be soft masked? Default is db.soft.mask = FALSE.
db.hard.mask	shall low complexity regions be hard masked? Default is db.hard.mask = FALSE.
blast.path	path to BLAST executables.

Author(s)

Hajk-Georg Drost

See Also

blast_protein_to_protein, blast_nucleotide_to_protein, blast_protein_to_nucleotide, blast_best_hit

Examples

## Not run: 
blast_test <- blast_nucleotide_to_nucleotide(
                 query   = system.file('seqs/qry_nn.fa', package = 'metablastr'),
                 subject = system.file('seqs/sbj_nn.fa', package = 'metablastr'),
                 output.path = tempdir(),
                 db.import  = FALSE)
                 
 # look at results
 blast_test

## End(Not run)

drostlab/metablastr documentation built on Sept. 14, 2023, 10:43 a.m.