<p>A nucleotide sequence may be a part of a genome assembly. If so, just click the assembly link from the right panel and you'll be redirected to the assembly page. <a href="https://i.sstatic.net/jvtKd.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/jvtKd.png" alt="enter image description here" /></a>
In this assembly page, it says the assembly only contains one chromosome. <a href="https://i.sstatic.net/tIyXT.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/tIyXT.png" alt="enter image description here" /></a>
Assembly method is also available for some assemblies. <a href="https://i.sstatic.net/lotZz.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/lotZz.png" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2022-06-27T10:05:16.760Z
2022-06-27T10:05:16.760Z
Forrest Vigor
<p>I have downloaded my FASTA format files, that have the DNA sequences of the coding region of the genes and the DNA sequence of the complete genome, from NCBI. How can I recognize if these sequences have been assembled or not ?</p>
<p>In particular, I read this paper <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3416535/" rel="nofollow noreferrer">Genome Sequencing of a Genetically Tractable Pyrococcus furiosus Strain Reveals a Highly Dynamic Genome</a> and I downloaded the sequences that they indicate in <strong>Nucleotide sequence accession number</strong> where they say:</p>
<blockquote>
<p>The fully assembled DNA sequence of COM1 has been deposited in GenBank (accession number <a href="https://www.ncbi.nlm.nih.gov/nuccore/CP003685" rel="nofollow noreferrer">CP003685</a>).</p>
</blockquote>
<p>I clicked on the link <a href="https://www.ncbi.nlm.nih.gov/nuccore/CP003685" rel="nofollow noreferrer">CP003685</a> and I downloaded the DNA sequences that I mentioned at the beginning by clicking on &quot;Send to&quot;, then &quot;Complete Record&quot;,then &quot;File&quot; (in Choose Destination), then FASTA (in Format). For the cds file I made the same steps but clicking on &quot;Coding Sequences&quot; and I could do the same to have the sequences of the genes clicking on &quot;Gene Features&quot;. But are these sequences assembled? By reading the extract of the article I would say yes... but is there a way to know this from the FASTA files that I downloaded or the NCBI website ?</p>
<p>Moreover, why is it important to know how a sequence has been assembled (so which software has been used) ?</p>
<p>I apologize for my very basic questions and I thank you in advance.</p>

<fasta><genome><assembly><sequence-analysis><phylogenetics>
How to know if the DNA sequence has been assembled and why is it important to know how it was assembled?
# How to know if the DNA sequence has been assembled and why is it important to know how it was assembled?

(Asked by: username_0 on 2021-08-01)

I have downloaded my FASTA format files, that have the DNA sequences of the coding region of the genes and the DNA sequence of the complete genome, from NCBI. How can I recognize if these sequences have been assembled or not ?

In particular, I read this paper [Genome Sequencing of a Genetically Tractable Pyrococcus furiosus Strain Reveals a Highly Dynamic Genome](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3416535/) and I downloaded the sequences that they indicate in **Nucleotide sequence accession number** where they say:

> The fully assembled DNA sequence of COM1 has been deposited in GenBank (accession number [CP003685](https://www.ncbi.nlm.nih.gov/nuccore/CP003685)).

I clicked on the link [CP003685](https://www.ncbi.nlm.nih.gov/nuccore/CP003685) and I downloaded the DNA sequences that I mentioned at the beginning by clicking on "Send to", then "Complete Record",then "File" (in Choose Destination), then FASTA (in Format). For the cds file I made the same steps but clicking on "Coding Sequences" and I could do the same to have the sequences of the genes clicking on "Gene Features". But are these sequences assembled? By reading the extract of the article I would say yes... but is there a way to know this from the FASTA files that I downloaded or the NCBI website ?

Moreover, why is it important to know how a sequence has been assembled (so which software has been used) ?

I apologize for my very basic questions and I thank you in advance.

**Tags:** fasta, genome, assembly, sequence-analysis, phylogenetics

---

## 1 answers

### Answer by username_1 on 2022-06-27. Score: 2

A nucleotide sequence may be a part of a genome assembly. If so, just click the assembly link from the right panel and you'll be redirected to the assembly page. [![enter image description here](https://i.sstatic.net/jvtKd.png)](https://i.sstatic.net/jvtKd.png)
In this assembly page, it says the assembly only contains one chromosome. [![enter image description here](https://i.sstatic.net/tIyXT.png)](https://i.sstatic.net/tIyXT.png)
Assembly method is also available for some assemblies. [![enter image description here](https://i.sstatic.net/lotZz.png)](https://i.sstatic.net/lotZz.png)


---

