Author: Danielle Novick
Last Update: February 15, 2017
Creation Date: October 24, 2017
Modified Date: Febuary 28, 2018 by M. Joseph Tomlinson IV
Created Summary Report file, Built in ability to Change Databases and Perform Organism Searches, Split the Blast results into two files (Hit vs. No Hits), Fixed some minor issues
This program takes a sample of sequences from a fastq file, trims the low quality ends, BLASTs them, fetches additional info from NCBI, and produces a tabular report.
Python 3 + the following packages
- biopython (download here: http://biopython.org/wiki/Download)
- urllib
- sys
- random
- argparse
- time
- collections
- numpy
To run the program with all default settings, use the following command.
python <scriptname> <filename> --email <email>
For example,
python FastqBLAST.py demo_data.fastq --email myemail@udel.edu
Running python FastqBLAST.py --help should return the following help file with information about all of the parameters.
usage: FastqBLAST.py [-h] --email EMAIL [--ascii64 ASCII64] [--nPercent NPERCENT]
[--nAbsolute NABSOLUTE] [--leadingQ LEADINGQ]
[--trailingQ TRAILINGQ] [--hitlistSize HITLISTSIZE] [--database DATABASE]
filename
This script takes a sample of sequences from a fastq file, trims the low
quality ends, BLASTs them, fetches additional info from NCBI, and produces a
report.
positional arguments:
filename The filename of the fastq file you wish to sample and
BLAST
optional arguments:
-h, --help show this help message and exit
--ascii64 ASCII64, -a ASCII64
Select true if Phred quality scores are encoded as
ASCII 64 (most are ASCII 33), default is False
--nPercent NPERCENT, -np NPERCENT
A float between 0 and 100, this argument takes
precedence over nAbsolute, default is 0
--nAbsolute NABSOLUTE, -na NABSOLUTE
An integer between 0 and the number of sequences in
your fastq file, this argument is superseded by
nPercent, default is 100
--leadingQ LEADINGQ, -lq LEADINGQ
The minimum quality required to keep a base at the
leading end of a read, default is 20
--trailingQ TRAILINGQ, -tq TRAILINGQ
The minimum quality required to keep a base at the
trailing end of a read, default is 20
--hitlistSize HITLISTSIZE, -hs HITLISTSIZE
The number of blast hits to keep for the final report,
default is 1
--taxID TAXID, -ID
The specific entrez species ID, to limit the blast search
to that organism, default is None
Example Species Entrez IDs:
chickens - 9031
humans - 9606
mouse - 10090
giant panda - 9646
--database DATABASE, -db DATABASE
NCBI database used in blast search,
default is nt
Example Database Names from NCBI:
nt - nucleotide database (sequences from tons of databases)
est_human - human subset of EST database
est_mouse - mouse subset of EST database
Note: EST stands for "Expressed Sequence TAG"
There are many more databases that can be blasted and a
full breakdown of NCBI databases can be found at the following link:
https://www.ncbi.nlm.nih.gov/books/NBK62345/#_blast_ftp_site_The_blastdb_subdirectory/
required named arguments:
--email EMAIL, -e EMAIL
A valid email address is required to use NCBI tools
and will be used if NCBI observes requests that
violate their policies.
- Wrap the BLAST function in a try/except block to make 2-3 attempts before giving up and throwing the error about the query being rejected.
- Use the final tabular report to calculate some summary statistics and maybe make some charts based on that output
- Include info in tabular report for sequences that result in "NO HIT", such as trimmed sequence length. Right now it's just a catch-all.