Separate fasta file for each locus

Question

[NM]

Greetings all,

I'm currently working on a molecular ecological study and have a fasta file containing both alleles for 50 loci from 8 individuals. Some of the programs I want to use require a separate fasta file for each locus, and I'm trying to find a way to group the data into files based on their catalog locus ID.

My data currently looks like this:

    >CLocus_2857_Sample_8_Locus_15367_Allele_0 [Test_1]  
AATTCGCGGTGGGGCTCTACAGGCAGCAGAATCCCTTCAGCACCCAGCCCAGGGCTGCCCTGGAGAAGGTCTGGATGTGCAGTGAATGAGATGGGGCCACAAGAAATGTGAGCTGAAGTCACGGGATGGATCCTCAGGCTGC
    >CLocus_2857_Sample_8_Locus_15367_Allele_1 [Test_1]  
AATTCGCGGTGGGGCTCTACAGGCAGCAGAATCCCTTCAGCACCCAGCCCAGGGCTGCCCTGGAGAAGGTCTGGATGTGCAGTGAATGAGATGGGGCCACAAGAAATGTGAGCTGAAGTCACGGGATGGATCCTCAGGCTGC
    >CLocus_2886_Sample_0_Locus_62236_Allele_0 [Test_2]  
AATTCAGTGTGGTGGTCTTCCTGGACTGGGTCACGGCCTTTTTTTGTGGGATGCACGTGTGCTTTGTGTGTTTGTGTGTGACCAAAAGCTAAATTAATTGGAAAATGAGTCTGTACTGTTTTGCAAATATGTTAAATGATGT
    >CLocus_2886_Sample_0_Locus_62236_Allele_1 [Test_2]  
AATTCAGTGTGGTGGTCTTCCTGGACTGGGTCACGGCCTTTTTTTGTGGGATGCACGTGTGCTTTGTGTGTTTGTGTGTGACCAAAAGCTAAATTAATTGGAAAATGAGTCTGTACTGTTTTGCAAATATGTTAAATGATGT

Where the number 'CLocus_X' is what I want to group them by.

I think the answer lies with using the awk tool, but my attempts so far have been clumsy and unsuccessful - I'm new to scripting, and stumped. I've found similar answers on here, but nothing that handles .fasta files with the same syntax.

Any advice would be hugely appreciated! Thank you all for your time.

[Pierre Lindenbaum]

it doesn't look like 'fasta', there is only one line per record including name AND sequence (?)

[NM]

Apologies, there should be two lines per record, one for the name and one for the sequence - it looked normal when I pasted it into the box. I'll edit it to properly reflect the format.

Answer 1

[cpad0112]

$  grep -Po '(?<=^>)[A-Za-z]*_[0-9]*(?=.*)' test.fa |  uniq |  parallel 'grep -A 1 {} test.fa > {}.fa'

output:

$ cat CLocus_2886.fa 
>CLocus_2886_Sample_0_Locus_62236_Allele_0 [Test_2] 
AATTCAGTGTGGTGGTCTTCCTGGACTGGGTCACGGCCTTTTTTTGTGGGATGCACGTGTGCTTTGTGTGTTTGTGTGTGACCAAAAGCTAAATTAATTGGAAAATGAGTCTGTACTGTTTTGCAAATATGTTAAATGATGT
>CLocus_2886_Sample_0_Locus_62236_Allele_1 [Test_2] 
AATTCAGTGTGGTGGTCTTCCTGGACTGGGTCACGGCCTTTTTTTGTGGGATGCACGTGTGCTTTGTGTGTTTGTGTGTGACCAAAAGCTAAATTAATTGGAAAATGAGTCTGTACTGTTTTGCAAATATGTTAAATGATGT

$ cat CLocus_2857.fa 
>CLocus_2857_Sample_8_Locus_15367_Allele_0 [Test_1] 
AATTCGCGGTGGGGCTCTACAGGCAGCAGAATCCCTTCAGCACCCAGCCCAGGGCTGCCCTGGAGAAGGTCTGGATGTGCAGTGAATGAGATGGGGCCACAAGAAATGTGAGCTGAAGTCACGGGATGGATCCTCAGGCTGC
>CLocus_2857_Sample_8_Locus_15367_Allele_1 [Test_1] 
AATTCGCGGTGGGGCTCTACAGGCAGCAGAATCCCTTCAGCACCCAGCCCAGGGCTGCCCTGGAGAAGGTCTGGATGTGCAGTGAATGAGATGGGGCCACAAGAAATGTGAGCTGAAGTCACGGGATGGATCCTCAGGCTGC

input:

$ cat test.fa
>CLocus_2857_Sample_8_Locus_15367_Allele_0 [Test_1] 
AATTCGCGGTGGGGCTCTACAGGCAGCAGAATCCCTTCAGCACCCAGCCCAGGGCTGCCCTGGAGAAGGTCTGGATGTGCAGTGAATGAGATGGGGCCACAAGAAATGTGAGCTGAAGTCACGGGATGGATCCTCAGGCTGC
>CLocus_2857_Sample_8_Locus_15367_Allele_1 [Test_1] 
AATTCGCGGTGGGGCTCTACAGGCAGCAGAATCCCTTCAGCACCCAGCCCAGGGCTGCCCTGGAGAAGGTCTGGATGTGCAGTGAATGAGATGGGGCCACAAGAAATGTGAGCTGAAGTCACGGGATGGATCCTCAGGCTGC
>CLocus_2886_Sample_0_Locus_62236_Allele_0 [Test_2] 
AATTCAGTGTGGTGGTCTTCCTGGACTGGGTCACGGCCTTTTTTTGTGGGATGCACGTGTGCTTTGTGTGTTTGTGTGTGACCAAAAGCTAAATTAATTGGAAAATGAGTCTGTACTGTTTTGCAAATATGTTAAATGATGT
>CLocus_2886_Sample_0_Locus_62236_Allele_1 [Test_2] 
AATTCAGTGTGGTGGTCTTCCTGGACTGGGTCACGGCCTTTTTTTGTGGGATGCACGTGTGCTTTGTGTGTTTGTGTGTGACCAAAAGCTAAATTAATTGGAAAATGAGTCTGTACTGTTTTGCAAATATGTTAAATGATGT

[Joe]

It’s probably worth mentioning that this solution requires linearised sequences (though I also assume thats what OP has).

[NM]

EDIT: The command works now - just had to load the parallel tool first. Thank you again!

Thank you for the quick response!

I can get the first half of the command to work fine - it outputs a list of the CLocus ID numbers. However, I can't get 'parallel' to function on the computing cluster I'm working from.

I've tried using xargs as a substitute but when I enter the command as follows:

grep -Po '(?<=^>)[A-Za-z]*_[0-9]*(?=.*)' ./batch_1.samples.fa | uniq | xargs grep -A 1 {} batch_1.samples.fa > {}.fa

I get a list of errors like this:

grep: CLocus_2857: No such file or directory grep: CLocus_2886: No such file or directory etc.

From what I can tell, it's trying to find files named after the CLocus IDs instead of searching -for- the CLocus IDs in the samples.fa file. Keeping the single quotes around the entire second command seems to treat the entire string as a filename/directory.

What should I be changing? Thank you again for the help.

[cpad0112]

if you are on ubuntu/mint/debian:

sudo apt install parallel -y

This should install gnu-parallel.