<p>I think you could use <a href="http://circos.ca/" rel="nofollow noreferrer">circos</a> for this. The configuration is kind of tedious but it gives nice results. You would basically need to retrieve alignments coordinates and parse them into this format.</p>

<pre><code>scaf1 19720 31917 scaf2 28307 34227
scaf1 28307 34227 scaf2 19720 31917
</code></pre>

<p>Example <a href="https://link.springer.com/article/10.1186%2Fs12915-017-0439-6" rel="nofollow noreferrer">figure</a>: 
<a href="https://i.sstatic.net/SrWwL.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/SrWwL.gif" alt="enter image description here"></a> </p>

CC BY-SA 3.0
2018-04-25T21:56:00.050Z
nice thanks! I has also been advised to try MUMmer (http://mummer.sourceforge.net), for easy dotplots
aechchiki
CC BY-SA 3.0
2018-04-25T11:30:14.077Z
2018-04-25T11:30:14.077Z
cmdoret
<p>I remember a few options for pairwise genome visualisation (which may be outdated BTW):</p>

<ul>
<li><a href="http://www.sanger.ac.uk/science/tools/artemis-comparison-tool-act" rel="nofollow noreferrer">ACT</a></li>
<li><a href="http://bioinfo.lifl.fr/yass/index.php" rel="nofollow noreferrer">YASS</a></li>
<li><a href="http://alitvteam.github.io/AliTV/" rel="nofollow noreferrer">aliTV</a></li>
<li><a href="http://www.bx.psu.edu/miller_lab/dist/README.lastz-1.02.00/README.lastz-1.02.00a.html" rel="nofollow noreferrer">LASTZ</a></li>
</ul>

CC BY-SA 3.0
2018-04-27T06:58:32.673Z
Thanks Léo! Maybe also worth of notice: (1) Geopard for GUI-dotplot: http://cube.univie.ac.at/gepard; (2) Ribbon - and actually (3) Mauve could also be run from command-line: https://sourceforge.net/p/ngopt/wiki/How_To_Score_Genome_Assemblies_with_Mauve/ 
Enough material for next bioinfo-DEE meeting I guess ;)
aechchiki
CC BY-SA 3.0
2018-04-26T14:40:45.757Z
2018-04-26T14:40:45.757Z
Leo Martins
<p>After a bit of digging, finally found exactly what I was looking for. I'll share here in case someone else was looking for the same thing.</p>

<p>I used a standard Nucleotide BLAST (blastn), coupled with <a href="http://mummer.sourceforge.net/" rel="nofollow noreferrer">MUMmer</a>. Short tutorial. </p>

<p>Assuming that <code>xn</code> &amp; <code>yn</code> are the couple of scaffolds I want to check if they are assembled together in the Pacbio assembly (a multi-fasta file):</p>

<p>1) first, I blasted the pair of Illumina scaffolds (as separate queries) to the PacBio genome (as subject): </p>

<p><code>blastn -query ../illumina_asm/scaffold_x1.fa -subject ../pacbio_asm/genome.fa &gt; out_scaffold_x1; blastn -query ../illumina_asm/scaffold_y1.fa -subject ../pacbio_asm/genome.fa &gt; out_scaffold_y1</code></p>

<p>The candidates PacBio scaffolds shall appear in the top blastn hits in both <code>out_scaffold_x1</code> &amp; <code>out_scaffold_y1</code>. </p>

<p>Let's assume we found one common scaffold only - corresponding to the fasta entry <code>pacbio_scaffold</code> in the PacBio genome. </p>

<p>2) extract the sequence of the target scaffold from the PacBio assembly, using <a href="http://www.htslib.org/doc/faidx.html" rel="nofollow noreferrer">samtools faidx</a>: </p>

<p><code>samtools faidx ../pacbio_asm/genome.fa; samtools faidx ../pacbio_asm/genome.fa 'pacbio_scaffold' &gt; pacbio_scaffold.fa</code></p>

<p>3) concatenate the Illumina scaffolds to analyze:</p>

<p><code>cat ../illumina_asm/scaffold_x1.fa ../illumina_asm/scaffold_y1.fa &gt; illumina_scaffolds.fa</code></p>

<p>4) compare the Illumina scaffolds to the PacBio assembly using <a href="https://github.com/garviz/MUMmer/blob/master/nucmer" rel="nofollow noreferrer">nucmer</a> from MUMmer:</p>

<p><code>nucmer --prefix=pacbio_scaffold pacbio_scaffold.fa illumina_scaffolds.fa</code></p>

<p>this will generate a <code>pacbio_scaffold.delta</code> file, used in the next step</p>

<p>5) filter the delta file to keep only the most meaningful alignments file using <a href="https://github.com/garviz/MUMmer/blob/master/delta-filter" rel="nofollow noreferrer">delta-filter</a> from MUMmer (avoiding confusing messy plots later):</p>

<p><code>delta-filter -m pacbio_scaffold.delta &gt; pacbio_scaffold.delta.m</code></p>

<p>6) use <a href="https://github.com/garviz/MUMmer/blob/master/mummerplot" rel="nofollow noreferrer">mummerplot</a> from MUMmer to achieve a graph:</p>

<p><code>mummerplot --png pacbio_scaffold.delta.m -R pacbio_scaffold.fa -Q illumina_scaffolds.fa --prefix=pacbio_scaffold -large -layout</code></p>

<p>On the x-axis, the PacBio scaffold they have in common. On the y-axis, the two Illumina scaffolds (separated by the horizontal grey abline). Colors correspond to the orientation. </p>

<p>Example of Illumina scaffolds linked in the PacBio assembly: </p>

<p><a href="https://i.sstatic.net/7Oinb.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/7Oinb.png" alt="Example of Illumina scaffolds linked in the PacBio assembly"></a></p>

CC BY-SA 3.0
2018-04-26T16:36:35.927Z
If you prefer dotter plot: https://peerj.com/preprints/26567/. There is also `minimap2 -DP ref.fa query.fa|miniasm/minidot - > dot.eps`, though the visual is not as good as mummerplot.
user172818
CC BY-SA 3.0
2018-04-27T10:20:26.127Z
Also: (1) MashMap - repo has a dotplot script: https://github.com/marbl/MashMap  & (2) Assemblytics - requiring a nucmer delta file: http://assemblytics.com
aechchiki
CC BY-SA 3.0
2018-04-26T15:24:40.913Z
2018-04-26T15:24:40.913Z
aechchiki
<p>I was asked to check the synteny of some genes in two genome assemblies of the same species (PacBio &amp; Illumina). I was given two scaffolds couples (so 4 scaffolds total) in the Illumina genome and asked if they were assembled together in the PacBio assembly. </p>

<p>So, I proceeded with a DNA-DNA alignment with <a href="https://github.com/lh3/minimap2" rel="noreferrer">minimap2</a> of the two Illumina scaffolds on the PacBio whole genome. But I am not sure on how to directly use the sam file for the question I was asked. So I tried to visualize this alignment using <a href="http://darlinglab.org/mauve/mauve.html" rel="noreferrer">Mauve</a>. It worked for the first couple, but it failed (blank page) for the second couple of scaffolds. </p>

<p>Surely, Mauve is not the best option out, so can you suggest an alternative? This is a chordata genome. </p>

<phylogenetics><software-recommendation><mauve>
visualisation of genome alignment
# visualisation of genome alignment

(Asked by: username_0 on 2018-04-25)

I was asked to check the synteny of some genes in two genome assemblies of the same species (PacBio & Illumina). I was given two scaffolds couples (so 4 scaffolds total) in the Illumina genome and asked if they were assembled together in the PacBio assembly.

So, I proceeded with a DNA-DNA alignment with [minimap2](https://github.com/lh3/minimap2) of the two Illumina scaffolds on the PacBio whole genome. But I am not sure on how to directly use the sam file for the question I was asked. So I tried to visualize this alignment using [Mauve](http://darlinglab.org/mauve/mauve.html). It worked for the first couple, but it failed (blank page) for the second couple of scaffolds.

Surely, Mauve is not the best option out, so can you suggest an alternative? This is a chordata genome.

**Tags:** phylogenetics, software-recommendation, mauve

---

## 3 answers

### Answer by username_0 on 2018-04-26. Score: 4 | Accepted answer

After a bit of digging, finally found exactly what I was looking for. I'll share here in case someone else was looking for the same thing.

I used a standard Nucleotide BLAST (blastn), coupled with [MUMmer](http://mummer.sourceforge.net/). Short tutorial.

Assuming that `xn` & `yn` are the couple of scaffolds I want to check if they are assembled together in the Pacbio assembly (a multi-fasta file):

1) first, I blasted the pair of Illumina scaffolds (as separate queries) to the PacBio genome (as subject):

`blastn -query ../illumina_asm/scaffold_x1.fa -subject ../pacbio_asm/genome.fa > out_scaffold_x1; blastn -query ../illumina_asm/scaffold_y1.fa -subject ../pacbio_asm/genome.fa > out_scaffold_y1`

The candidates PacBio scaffolds shall appear in the top blastn hits in both `out_scaffold_x1` & `out_scaffold_y1`.

Let's assume we found one common scaffold only - corresponding to the fasta entry `pacbio_scaffold` in the PacBio genome.

2) extract the sequence of the target scaffold from the PacBio assembly, using [samtools faidx](http://www.htslib.org/doc/faidx.html):

`samtools faidx ../pacbio_asm/genome.fa; samtools faidx ../pacbio_asm/genome.fa 'pacbio_scaffold' > pacbio_scaffold.fa`

3) concatenate the Illumina scaffolds to analyze:

`cat ../illumina_asm/scaffold_x1.fa ../illumina_asm/scaffold_y1.fa > illumina_scaffolds.fa`

4) compare the Illumina scaffolds to the PacBio assembly using [nucmer](https://github.com/garviz/MUMmer/blob/master/nucmer) from MUMmer:

`nucmer --prefix=pacbio_scaffold pacbio_scaffold.fa illumina_scaffolds.fa`

this will generate a `pacbio_scaffold.delta` file, used in the next step

5) filter the delta file to keep only the most meaningful alignments file using [delta-filter](https://github.com/garviz/MUMmer/blob/master/delta-filter) from MUMmer (avoiding confusing messy plots later):

`delta-filter -m pacbio_scaffold.delta > pacbio_scaffold.delta.m`

6) use [mummerplot](https://github.com/garviz/MUMmer/blob/master/mummerplot) from MUMmer to achieve a graph:

`mummerplot --png pacbio_scaffold.delta.m -R pacbio_scaffold.fa -Q illumina_scaffolds.fa --prefix=pacbio_scaffold -large -layout`

On the x-axis, the PacBio scaffold they have in common. On the y-axis, the two Illumina scaffolds (separated by the horizontal grey abline). Colors correspond to the orientation.

Example of Illumina scaffolds linked in the PacBio assembly:

[![Example of Illumina scaffolds linked in the PacBio assembly](https://i.sstatic.net/7Oinb.png)](https://i.sstatic.net/7Oinb.png)

> **Comments:**
> **username_3**: If you prefer dotter plot: https://peerj.com/preprints/26567/. There is also `minimap2 -DP ref.fa query.fa|miniasm/minidot - > dot.eps`, though the visual is not as good as mummerplot.  
> **username_0**: Also: (1) MashMap - repo has a dotplot script: https://github.com/marbl/MashMap  & (2) Assemblytics - requiring a nucmer delta file: http://assemblytics.com  

---

### Answer by username_1 on 2018-04-25. Score: 3

I think you could use circos for this. The configuration is kind of tedious but it gives nice results. You would basically need to retrieve alignments coordinates and parse them into this format.
scaf1 19720 31917 scaf2 28307 34227
scaf1 28307 34227 scaf2 19720 31917

Example figure:

> **Comments:**
> **username_0**: nice thanks! I has also been advised to try MUMmer (http://mummer.sourceforge.net), for easy dotplots  

---

### Answer by username_2 on 2018-04-26. Score: 2

I remember a few options for pairwise genome visualisation (which may be outdated BTW):

* [ACT](http://www.sanger.ac.uk/science/tools/artemis-comparison-tool-act)
* [YASS](http://bioinfo.lifl.fr/yass/index.php)
* [aliTV](http://alitvteam.github.io/AliTV/)
* [LASTZ](http://www.bx.psu.edu/miller_lab/dist/README.lastz-1.02.00/README.lastz-1.02.00a.html)

> **Comments:**
> **username_0**: Thanks Léo! Maybe also worth of notice: (1) Geopard for GUI-dotplot: http://cube.univie.ac.at/gepard; (2) Ribbon - and actually (3) Mauve could also be run from command-line: https://sourceforge.net/p/ngopt/wiki/How_To_Score_Genome_Assemblies_with_Mauve/  Enough material for next bioinfo-DEE meeting I guess ;)  

---

