Illumina sequencing data from 1000genomes

[thsuk1]

Hi guys,

I have a question about Illumina sequencing data from
ftp://ftp-trace.ncbi.nih.gov/1000gen...sequence_read/

File:ERR004067.filt.fastq.gz 26795 KB
File:ERR004067_1.filt.fastq.gz 621514 KB
File:ERR004067_2.filt.fastq.gz 635159 KB

I know that ERR004067_1 and ERR004067_2 are for paired ends, but I don't know what ERR004067.flit.fastq.gz is.
I assumed that ERR004067.flit.fastq.gz is a merged file of ERR004067_1.filt.fastq.gz and ERR004067_2.filt.fastq.gz, but size of ERR004067.flit.fastq.gz is much smaller than the others.
What is ERR004067.flit.fastq.gz?

thanks.

[laura]

The 1000 genomes DCC filters the fastq when they retrieve it from the archive. The filtering criteria are described in this readme

ftp://ftp.1000genomes.ebi.ac.uk/vol1....sequence_data

If one half of a paired end passes the filter but the other half fails then the half that passes if put into a fragment file and this is named without the _1 or _2 and should be treated like a single ended fastq file