Hi folks:

I am trying to get raw RNASeq data from ENA and wonder how to know the length of the sequences in those FASTQ files without downloading them?

In the query design I follow their [guide][1], and use the "`nominal_length>XXX"` in the query, but this filtering mechanism doesn't work...

Thanks!

 [1]: http://www.ebi.ac.uk/ena/browse/search-rest
The Paired nominal length does not seem to work in the ENA query builder [here][1] or at least it doesn't autofill into the query box, but you can add it to the URL string. For example, in the query builder, select domain = read and Library layout= Paired and optionally a taxon name like Bacteria , then you get this query.

    tax_eq(2) AND library_layout="PAIRED"

Hit search and then add nominal length to the URL and get this [URL string][2] and query

    tax_eq(2) AND library_layout="PAIRED" AND nominal_length>300

The nominal_length is just a filter, so you may need to check read experiment XML for actual length and stdev.

UPDATE : add `&result=read_experiment&display=xml&download=txt` to the URL and parse `NOMINAL_LENGTH` from [the summary XML][3]

 [1]: http://www.ebi.ac.uk/ena/data/warehouse/search
 [2]: http://www.ebi.ac.uk/ena/data/warehouse/search?query=%22tax_eq%282%29%20AND%20library_layout=%22PAIRED%22%20AND%20nominal_length%3E300%22&domain=read
 [3]: http://www.ebi.ac.uk/ena/data/warehouse/search?query=%22tax_eq%282%29%20AND%20library_layout=%22PAIRED%22%20AND%20nominal_length%3E300%22&domain=read&result=read_experiment&display=xml&download=txt