<p>I am trying to calculate the total exonic length (in bp) in order to see where the coding-noncoding ratio of roughly 1% to 99% comes from.
We know all chromosomes total about 3 billion base pairs. So Is it correct to assume that coding regions would total about 30 million base pairs? I am looking at the numbers in the sources below, but nothing there adds up...</p>
<p>Take numbers from <a href="https://www.ncbi.nlm.nih.gov/genome/annotation_euk/Homo_sapiens/108/" rel="nofollow noreferrer">NCBI annothation</a> for example; specifically</p>
<p><a href="https://i.sstatic.net/UBhV4.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/UBhV4.jpg" alt="NCBI exon length" /></a></p>
<p>no matter how i count i can't get the expected ratio... What am  doing wrong?</p>
<p>Thank you!</p>
<p><a href="https://www.encodeproject.org/report/?type=Gene&amp;organism.scientific_name=Homo%20sapiens&amp;searchTerm=gene&amp;field=symbol&amp;field=notes" rel="nofollow noreferrer">https://www.encodeproject.org/report/?type=Gene&amp;organism.scientific_name=Homo%20sapiens&amp;searchTerm=gene&amp;field=symbol&amp;field=notes</a></p>
<p><a href="https://archive.vn/20130414235101/http://useast.ensembl.org/Homo_sapiens/Location/Chromosome?r=1" rel="nofollow noreferrer">https://archive.vn/20130414235101/http://useast.ensembl.org/Homo_sapiens/Location/Chromosome?r=1</a></p>

CC BY-SA 4.0
2020-07-07T00:59:45.203Z
cross-posted: https://www.biostars.org/p/447675/
burger
CC BY-SA 4.0
2020-07-07T01:16:50.080Z
There are a few different answers provided here: https://biology.stackexchange.com/questions/48110/how-is-the-size-of-a-gene-defined
burger
CC BY-SA 4.0
2020-07-07T01:42:18.823Z
Thank you, but this is a different question; my aim is to get the said ratio given the feature numbers, in my case the length of coding vs non-coding regions. The original response helped me by pointing out that i should focus on exons, rather than the entire gene region. So i searched and found some definitive numbers for exon length, and calculated in different combinations, but they still aren't adding up to the 99%-1% ratio. So i'm wondering if i'm missing something else here. Or whether i'm looking at the wrong features entirely.
janeu
CC BY-SA 4.0
2020-07-07T03:00:24.800Z
They are not adding up because you need exclude non-coding exons (non-CDS) and exclude overlapping features. The discussion I posted shows how to get coding regions. The only difference is that they are trying to get the average length and you need total length.
burger
<genome><phylogenetics><genetics><exon>
Coding vs non-coding DNA length
# Coding vs non-coding DNA length

(Asked by: username_0 on 2020-07-06)

I am trying to calculate the total exonic length (in bp) in order to see where the coding-noncoding ratio of roughly 1% to 99% comes from.
We know all chromosomes total about 3 billion base pairs. So Is it correct to assume that coding regions would total about 30 million base pairs? I am looking at the numbers in the sources below, but nothing there adds up...

Take numbers from [NCBI annothation](https://www.ncbi.nlm.nih.gov/genome/annotation_euk/Homo_sapiens/108/) for example; specifically

[![NCBI exon length](https://i.sstatic.net/UBhV4.jpg)](https://i.sstatic.net/UBhV4.jpg)

no matter how i count i can't get the expected ratio... What am doing wrong?

Thank you!

<https://www.encodeproject.org/report/?type=Gene&organism.scientific_name=Homo%20sapiens&searchTerm=gene&field=symbol&field=notes>

<https://archive.vn/20130414235101/http://useast.ensembl.org/Homo_sapiens/Location/Chromosome?r=1>

**Tags:** genome, phylogenetics, genetics, exon
> **Comments:**
> **username_1**: cross-posted: https://www.biostars.org/p/447675/  
> **username_1**: There are a few different answers provided here: https://biology.stackexchange.com/questions/48110/how-is-the-size-of-a-gene-defined  
> **username_0**: Thank you, but this is a different question; my aim is to get the said ratio given the feature numbers, in my case the length of coding vs non-coding regions. The original response helped me by pointing out that i should focus on exons, rather than the entire gene region. So i searched and found some definitive numbers for exon length, and calculated in different combinations, but they still aren't adding up to the 99%-1% ratio. So i'm wondering if i'm missing something else here. Or whether i'm looking at the wrong features entirely.  
> **username_1**: They are not adding up because you need exclude non-coding exons (non-CDS) and exclude overlapping features. The discussion I posted shows how to get coding regions. The only difference is that they are trying to get the average length and you need total length.  

---

## 0 answers

