I will remove the GC bin in my future assemblies, thank you for the input. While I do not have to worry about accidental cocultures (none of the bacteria I work with are culturable), I do sometimes have a difficult time separating genomes by coverage because the variance in the contigs belonging to one genome can overlap the with the contigs belonging to another.
Seqanswers Leaderboard Ad
Collapse
Announcement
Collapse
No announcement yet.
X
-
For a denovo assembly, I guess you could use the GC filter to assemble a draft genome. You could then use this draft as a reference for future assemblies using contigs filtered using other methods, as you mentioned jvanleuven.
I'm new at all this too, so it's a good learning experience to try these different methods.
Comment
-
Tried A5 pipeline on Hiseq raw data:
Hi Koadman,
My apologies for the delay in getting back to you. Had to go overseas!
I tried the new A5 pipeline, and although it worked, I'm having the same problem, that I have with the other assembly methods. The genome size at the end of A5 is 11.3mb when it should be 4mb. I'm attaching the log file that qsub (cluster) generated.
Our samples are very hard to culture axenically.. so I guess thats what the probem is. Though I didnt have this problem for the last set of samples of the same species (used the GA2 for genome sequencing, and not the Hiseq).Do you have any suggestions on what approach I can take now? I was thinking of mapping the fasta output of A5 onto my reference genome using Bowtie or Soapaligner.Attached Files
Comment
-
Great to hear that A5 assembled your genomes. Yes, sounds like you've got a coculture on your hands. I would be surprised to if this is a Hiseq vs. GA2 issue, unless your samples were multiplexed with other organisms and there were barcode read failures or the person who prepped the library and loaded the lane accidentally mixed libraries. Probably unlikely, and not really a Hiseq issue but a possible sequencing issue to rule out.
Mapping contigs back to a high quality reference is a good approach for separating the "contaminant" from the desired genome. You might still miss some small scaffolds that belong in your isolate. The best way to minimize that problem is to have the best possible scaffolds!
Might be interesting to find out what else is living in your sample! I've had pretty good luck in the past picking out the dominant organisms in a mixed sample using EMIRGE, a 16s-based short read taxonomy analysis pipeline. It might tell you whether the contaminants are things you expect to be living in the environment with your desired organism or things that came from somewhere else in the lab. You might also try metAMOS on the raw reads or even a simple BLAST of the A5 scaffolds against nr and subsequent MEGAN.
Comment
Latest Articles
Collapse
-
by seqadmin
Metagenomics has improved the way researchers study microorganisms across diverse environments. Historically, studying microorganisms relied on culturing them in the lab, a method that limits the investigation of many species since most are unculturable1. Metagenomics overcomes these issues by allowing the study of microorganisms regardless of their ability to be cultured or the environments they inhabit. Over time, the field has evolved, especially with the advent...-
Channel: Articles
09-23-2024, 06:35 AM -
-
by seqadmin
During the COVID-19 pandemic, scientists observed that while some individuals experienced severe illness when infected with SARS-CoV-2, others were barely affected. These disparities left researchers and clinicians wondering what causes the wide variations in response to viral infections and what role genetics plays.
Jean-Laurent Casanova, M.D., Ph.D., Professor at Rockefeller University, is a leading expert in this crossover between genetics and infectious...-
Channel: Articles
09-09-2024, 10:59 AM -
ad_right_rmr
Collapse
News
Collapse
Topics | Statistics | Last Post | ||
---|---|---|---|---|
Started by seqadmin, 10-02-2024, 04:51 AM
|
0 responses
13 views
0 likes
|
Last Post
by seqadmin
10-02-2024, 04:51 AM
|
||
Started by seqadmin, 10-01-2024, 07:10 AM
|
0 responses
21 views
0 likes
|
Last Post
by seqadmin
10-01-2024, 07:10 AM
|
||
Started by seqadmin, 09-30-2024, 08:33 AM
|
0 responses
25 views
0 likes
|
Last Post
by seqadmin
09-30-2024, 08:33 AM
|
||
Started by seqadmin, 09-26-2024, 12:57 PM
|
0 responses
18 views
0 likes
|
Last Post
by seqadmin
09-26-2024, 12:57 PM
|
Comment