<p>The thinkness indicates whether something is an intron, a coding exon, or a UTR. The very thin lines are introns, the full thickness boxes are coding exons and the thinner boxes are UTRs.</p>
<p>UTRs, untranslated regions, are exons, they are included in the final mRNA, but they don't code for protein. So, by convention, they are shown as thinner exons to give the user a visual indication that although this is still an exonic region, it's a special one.</p>
<p>I don't really know where this is documented, it's pretty standard across all genome browsers and bam visualizers I know though so it's a common idiom.</p>

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2023-04-20T11:06:11.477Z
2023-05-12T08:31:47.967Z
2023-05-12T08:31:47.967Z
terdon
<p>What does the IGV refseq genes with three different thicknesses of lines mean?</p>
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What does the IGV refseq genes with three different thicknesses of lines mean?
# What does the IGV refseq genes with three different thicknesses of lines mean?

(Asked by: username_0 on 2023-04-20)

What does the IGV refseq genes with three different thicknesses of lines mean?

[![enter image description here](https://i.sstatic.net/Q6IBK.png)](https://i.sstatic.net/Q6IBK.png)

**Tags:** igv

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## 1 answers

### Answer by username_1 on 2023-04-20. Score: 6 | Accepted answer

The thinkness indicates whether something is an intron, a coding exon, or a UTR. The very thin lines are introns, the full thickness boxes are coding exons and the thinner boxes are UTRs.

UTRs, untranslated regions, are exons, they are included in the final mRNA, but they don't code for protein. So, by convention, they are shown as thinner exons to give the user a visual indication that although this is still an exonic region, it's a special one.

I don't really know where this is documented, it's pretty standard across all genome browsers and bam visualizers I know though so it's a common idiom.


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