-
Notifications
You must be signed in to change notification settings - Fork 1
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
5 changed files
with
129 additions
and
22 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
|
@@ -391,3 +391,5 @@ heatmap with high number of rows` tool | |
|
||
--> `24` | ||
- `Run Tool` | ||
|
||
--- |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -1,20 +1,125 @@ | ||
To compare DESeq2, edgeR and limma, we are now going to collect the lists of genes | ||
generated in the three corresponding histories in a new history which we name `DESeq2, edgeR, | ||
limma comparisons`. | ||
|
||
Thus, create this history `DESeq2, edgeR, limma comparisons`, and from this history, copy | ||
the required datasets from all three histories. | ||
|
||
- [x] in the history `PRJNA630433 DESeq2 analysis`, get the datasets | ||
- top gene lists - oriented | ||
- top up-regulated gene lists | ||
- top down-regulated gene lists | ||
- [x] in the history `PRJNA630433 edgeR analysis`, get the datasets | ||
- edgeR top gene lists - oriented | ||
- edgeR top up-regulated gene lists | ||
- edgeR top down-regulated gene lists | ||
- [x] in the history `PRJNA630433 limma analysis`, get the datasets | ||
- limma top gene lists - oriented | ||
- limma top up-regulated gene lists | ||
- limma top down-regulated gene lists | ||
We are now going to make a quick comparison of the three Differential Expression analysis | ||
packages, DESeq2, edgeR, and limma, using some results generated in the histories | ||
"PRJNA630433 DESeq2 analysis", "PRJNA630433 edgeR analysis" and "PRJNA630433 limma | ||
analysis". | ||
|
||
## Collect datasets | ||
|
||
Thus, create a new history `DESeq2, edgeR, limma comparisons`, and from this history, | ||
import (menu `copy datasets`) the required datasets. | ||
|
||
- [x] in the history `PRJNA630433 DESeq2 analysis`, copy the dataset | ||
- `DESeq_All_DE_genes` (This should be the second to last file of the history). It is a | ||
simple list of gene names with a single header) | ||
- [x] in the history `PRJNA630433 edgeR analysis`, get the dataset | ||
- `edgeR_All_DE_genes` (Also probably the second to last file of the history). | ||
- [x] in the history `PRJNA630433 limma analysis`, get the dataset | ||
- `limma_All_DE_genes` | ||
|
||
:warning: You can stay in the current "PRJNA630433 edgeR analysis" and "PRJNA630433 limma | ||
analysis" history to execute these 3 copies. Just change the `Source History` of the copy | ||
dashboard, and be sure that, each time, the `Destination History` is `DESeq2, edgeR, limma | ||
comparisons` | ||
|
||
Your starting history should look like this: | ||
|
||
![](images/history_comparison.png){width="300"} | ||
|
||
## Venn diagram | ||
|
||
The three datasets contain a list of significantly deregulated (up and down) genes in | ||
either of the three comparisons (Mo vs Dc, Oc vs Dc, Oc vs Mo), as returned by DESeq2, | ||
edgeR or Limma-voom, respectively. | ||
|
||
Note that, although there is no quantitative information anymore in these lists, we can | ||
look at their overlaps using a Venn diagram approach. | ||
|
||
We are going to perform this analysis using the Galaxy tool `Venn diagram [JVenn]` | ||
|
||
!!! info "![](images/tool_small.png){width="25" align="absbottom"} `Venn diagram [JVenn]` settings" | ||
- **1: List to compare** | ||
- Enter your list | ||
|
||
--> `Input file containing your list` | ||
- Select your file | ||
|
||
--> `DESeq_All_DE_genes` | ||
|
||
- Does file contain header? | ||
|
||
--> `Yes` | ||
- Column number on which apply the comparison | ||
|
||
--> `c1` | ||
|
||
- Enter the name of this list | ||
|
||
--> `DESeq2` | ||
|
||
- **2: List to compare** | ||
- Enter your list | ||
|
||
--> `Input file containing your list` | ||
- Select your file | ||
|
||
--> `edgeR_All_DE_genes` | ||
|
||
- Does file contain header? | ||
|
||
--> `Yes` | ||
- Column number on which apply the comparison | ||
|
||
--> `c1` | ||
|
||
- Enter the name of this list | ||
|
||
--> `edgeR` | ||
|
||
- **3: List to compare** (after clicking :heavy_plus_sign:**`Insert List to compare`**) | ||
- Enter your list | ||
|
||
--> `Input file containing your list` | ||
- Select your file | ||
|
||
--> `limma_All_DE_genes` | ||
|
||
- Does file contain header? | ||
|
||
--> `Yes` | ||
- Column number on which apply the comparison | ||
|
||
--> `c1` | ||
|
||
- Enter the name of this list | ||
|
||
--> `limma-voom` | ||
|
||
- Run tool | ||
|
||
The venn diagram return by the tool should look like this: | ||
|
||
<center>![](images/jVenn_chart.png){width="500"}</center> | ||
|
||
## Discussion | ||
|
||
DESeq2 appears as a less stringent "Caller" than edgeR: overall only a few genes (10 + 23) | ||
are called by edgeR but not by DESeq2. This is expected because normalisation and statistical | ||
tests (exact Fisher's test) are similar between DESeq2 and edgeR. However DESeq perfoms an | ||
original step of variance shrinking and the authors of DESeq2 claim that this data transformation | ||
allows to call confidently more DE genes without increasing the False Detection Rate (type | ||
I error). Taking only the DE genes common to both DESeq2 and edgeR would allow to further | ||
improve the false detection rate, at the expanse of increased False Negative rate (type II | ||
error) | ||
|
||
Limma appears a bit "transversal" to DESeq2 and edgeR: beside a core of common gene (2713), | ||
Limma calls 83 genes also called by DESeq2 and 23 genes also called by edgeR, respectively. | ||
|
||
Strikingly however, limma calls a substantial number of genes which are not called either | ||
by DESeq2 or edgeR. This is likely due to the radically different approach of Limma-Zoom, | ||
in part inherited from methods to analyse continuous microarray variables (which modele | ||
gene expression variables as Gaussians). | ||
|
||
Note that although Limma is likely less adapted to analysis of discrete read counts, it | ||
performs relatively well in light of the fact that only ~10 % of DE genes called by limma | ||
are not called by DESeq2 or edgeR ! | ||
--- |
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Loading
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.