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Does anyone know what this output in tophat mean? How much of a problem is it?
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I am curious too...
I am curious as well as to what this truly means and if it should be a concern. I encountered it on my latest runs in which I am using the Ensembl version of the human genome assembly. An example of the warning displayed is:
Should we be concerned?[Sun Aug 08 23:20:23 2010] Beginning TopHat run (v1.0.14)
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[Sun Aug 08 23:20:23 2010] Preparing output location brain/
[Sun Aug 08 23:20:23 2010] Checking for Bowtie index files
[Sun Aug 08 23:20:23 2010] Checking for reference FASTA file
[Sun Aug 08 23:20:23 2010] Checking for Bowtie
Bowtie version: 0.12.5.0
[Sun Aug 08 23:20:23 2010] Checking reads
seed length: 36bp
format: fastq
quality scale: phred33 (default)
[Sun Aug 08 23:23:07 2010] Mapping reads against Homo_sapiens.GRCh37.59 with Bowtie
[Sun Aug 08 23:26:43 2010] Joining segment hits
[Sun Aug 08 23:27:09 2010] Mapping reads against Homo_sapiens.GRCh37.59 with Bowtie
[Sun Aug 08 23:31:02 2010] Joining segment hits
[Sun Aug 08 23:31:26 2010] Searching for junctions via segment mapping
[Sun Aug 08 23:46:58 2010] Retrieving sequences for splices
[Sun Aug 08 23:52:48 2010] Indexing splices
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
Warning: Encountered reference sequence with only gaps
[Sun Aug 08 23:54:58 2010] Mapping reads against segment_juncs with Bowtie
[Sun Aug 08 23:58:35 2010] Joining segment hits
[Sun Aug 08 23:59:00 2010] Mapping reads against segment_juncs with Bowtie
[Mon Aug 09 00:02:49 2010] Joining segment hits
[Mon Aug 09 00:03:13 2010] Reporting output tracks
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Run complete [00:45:40 elapsed]
-steve -
Did you find the answer to this warning message? I have similar problem with my data as well and appreciate if you can let me know how to deal with it.Comment
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I never did find an answer to this. I didn't see any problems associated it with it either though.Comment
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-------bump-------
I also get this using Ensembl human reference (v. 68)Comment
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Is it because you are using a repeat masked genome and possibly some of the sequences have been completely masked? I've seen this in other, less complete genomes, so I'm unsure if this would be the case with the human genome.Comment
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Thanks Wallysb01, that's propably it. I am using a soft-masked reference (low complexity regions are lowercase).Comment
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I also have the same error message, when I use the Homo_sapiens.GRCh37.71.dna.toplevel reference.
Does this upper/lower case issue influence the mapping/counting outcome?Comment
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I also have the same warning message with Homo_sapiens.GRCh37.71.dna.toplevel reference. anyone can explain it?Comment
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-----------BUMP-----------Originally posted by digitonin View Post
First of all, sorry for bumping such a old post, but this problem still persists...
Does anyone found a reason why does this happens?
I have obtained this same warning message when using the current Drosophila melanogaster reference (r6.03; BDGP5.78)Comment
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Hugo,
This probably has to do with the lowercase or the use of N's in the reference. Either way, it is not a problem.Comment
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Hi,
I am using bowtie 1.1.2 and I get the same message -
encountered reference sequence with gaps
My genome is not repmasked and has the following type of header
>ta_IWGSC_CSSassembly_1as_v2_44039
Does such a warning interfere with the bowtie-build in anyway?Comment
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This will happen whenever you have cases like this
or thisCode:>chr1 >chr2 ACAGCTACT
It's just a warning, which means that there won't be an issue with index creation, but you should really fix your fasta files.Code:>chr3 NNNNNNN >chr4 ACGTAGCTGACT
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Cancer survival rates have significantly increased in the last few decades in the United States, reaching a combined 70% 5-year survival rate by 2021. Behind this number, there are years of research to find new therapies, drug targets, and early detection methods. But there is one core challenge that keeps slowing down these advances, and it’s about drug resistance.
There is no single reason why many patients don’t respond to treatment as expected. Cancer is...Today, 05:17 AM -
Love this - good data definitely starts from good input, and poor input can only give relatively poor data. I particularly like the mention of Nanodrop/absorbance based methods for quantification. It's such a toss up if you'll get an accurate reading or what amounts to a randomly generated number, and a lot of library/sequencing related issues can be traced back to poor quant.07-01-2026, 11:43 AM
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I’m not a sequencing expert. I’m a purification scientist who uses NGS to evaluate workflows my group develops. With this perspective, we think about the sample first and the NGS workflow second. The sequencer is an exceptionally honest reporter, but it can only report on what you give it, so whether you get clean, interpretable data from an NGS workflow is largely determined before you begin.
Here are nine questions we think about, in roughly the order they matter, before...
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