Normalization for two bulk RNA-Seq samples to enable reliable fold-change estimation between genes












2












$begingroup$


I have two bulk RNA-Seq samples, already tpm-normalized.



I would like to know what is a reasonable normalization procedure to enable downstream log fold-change estimation.



The distribution of the two samples using the common set of genes looks similar:



TPM distribution



However, the two samples have only been tpm-normalized, is it enough to guarantee reliable fold-change estimation? Should I use another normalization procedure, e.g. Quantile Normalization, before comparison?



My objective is to define a signature using the genes that are up-regulated in Sample1 with respect to Sample0, and vice versa. I'm using log fold-changes, but I'm concerned that their value may be affected by each sample distribution.



Do you also have suggestions for the definition of up-regulated genes with these data?



scatter










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    2












    $begingroup$


    I have two bulk RNA-Seq samples, already tpm-normalized.



    I would like to know what is a reasonable normalization procedure to enable downstream log fold-change estimation.



    The distribution of the two samples using the common set of genes looks similar:



    TPM distribution



    However, the two samples have only been tpm-normalized, is it enough to guarantee reliable fold-change estimation? Should I use another normalization procedure, e.g. Quantile Normalization, before comparison?



    My objective is to define a signature using the genes that are up-regulated in Sample1 with respect to Sample0, and vice versa. I'm using log fold-changes, but I'm concerned that their value may be affected by each sample distribution.



    Do you also have suggestions for the definition of up-regulated genes with these data?



    scatter










    share|improve this question









    $endgroup$















      2












      2








      2





      $begingroup$


      I have two bulk RNA-Seq samples, already tpm-normalized.



      I would like to know what is a reasonable normalization procedure to enable downstream log fold-change estimation.



      The distribution of the two samples using the common set of genes looks similar:



      TPM distribution



      However, the two samples have only been tpm-normalized, is it enough to guarantee reliable fold-change estimation? Should I use another normalization procedure, e.g. Quantile Normalization, before comparison?



      My objective is to define a signature using the genes that are up-regulated in Sample1 with respect to Sample0, and vice versa. I'm using log fold-changes, but I'm concerned that their value may be affected by each sample distribution.



      Do you also have suggestions for the definition of up-regulated genes with these data?



      scatter










      share|improve this question









      $endgroup$




      I have two bulk RNA-Seq samples, already tpm-normalized.



      I would like to know what is a reasonable normalization procedure to enable downstream log fold-change estimation.



      The distribution of the two samples using the common set of genes looks similar:



      TPM distribution



      However, the two samples have only been tpm-normalized, is it enough to guarantee reliable fold-change estimation? Should I use another normalization procedure, e.g. Quantile Normalization, before comparison?



      My objective is to define a signature using the genes that are up-regulated in Sample1 with respect to Sample0, and vice versa. I'm using log fold-changes, but I'm concerned that their value may be affected by each sample distribution.



      Do you also have suggestions for the definition of up-regulated genes with these data?



      scatter







      rna-seq normalization fold-change






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      share|improve this question











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      asked 3 hours ago









      gc5gc5

      721216




      721216






















          3 Answers
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          $begingroup$

          It's not a good idea to do tpm normalisation prior to differential expression analysis, because the actual read counts are useful to determine shot noise and statistical significance. DESeq2 includes read normalisation as part of its methods for differential expression analysis.






          share|improve this answer









          $endgroup$













          • $begingroup$
            I agree with TPM for a lot of reasons, unfortunately the data was already in TPM. Can you explain more about how read counts are useful to determine shot noise and statistical significance? Thanks
            $endgroup$
            – gc5
            1 hour ago



















          2












          $begingroup$

          What I have generally done in the past is to process the data using voom in the limma package for bulk RNASeq. Inside voom you can call for different normalization methods to be used - "TMM" works fine for me and, is advocated by many in the field.



          voom will output an object containing the normalized expression values in a log2 scale, which, also in my experience, has worked out just fine for calculating log fold changes.



          Check out this link for more info on the package as well as normalization methods: https://www.bioconductor.org/packages/devel/workflows/vignettes/RNAseq123/inst/doc/limmaWorkflow.html
          It is a very thorough introduction to the package and all of its capabilities.



          Good luck!






          share|improve this answer









          $endgroup$





















            0












            $begingroup$

            You have only two samples?



            You aren't going to be able to draw strong conclusions from that no matter what you do. Clever statistics don't work without replicates.






            share|improve this answer









            $endgroup$













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              3 Answers
              3






              active

              oldest

              votes








              3 Answers
              3






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              2












              $begingroup$

              It's not a good idea to do tpm normalisation prior to differential expression analysis, because the actual read counts are useful to determine shot noise and statistical significance. DESeq2 includes read normalisation as part of its methods for differential expression analysis.






              share|improve this answer









              $endgroup$













              • $begingroup$
                I agree with TPM for a lot of reasons, unfortunately the data was already in TPM. Can you explain more about how read counts are useful to determine shot noise and statistical significance? Thanks
                $endgroup$
                – gc5
                1 hour ago
















              2












              $begingroup$

              It's not a good idea to do tpm normalisation prior to differential expression analysis, because the actual read counts are useful to determine shot noise and statistical significance. DESeq2 includes read normalisation as part of its methods for differential expression analysis.






              share|improve this answer









              $endgroup$













              • $begingroup$
                I agree with TPM for a lot of reasons, unfortunately the data was already in TPM. Can you explain more about how read counts are useful to determine shot noise and statistical significance? Thanks
                $endgroup$
                – gc5
                1 hour ago














              2












              2








              2





              $begingroup$

              It's not a good idea to do tpm normalisation prior to differential expression analysis, because the actual read counts are useful to determine shot noise and statistical significance. DESeq2 includes read normalisation as part of its methods for differential expression analysis.






              share|improve this answer









              $endgroup$



              It's not a good idea to do tpm normalisation prior to differential expression analysis, because the actual read counts are useful to determine shot noise and statistical significance. DESeq2 includes read normalisation as part of its methods for differential expression analysis.







              share|improve this answer












              share|improve this answer



              share|improve this answer










              answered 2 hours ago









              gringergringer

              7,79221049




              7,79221049












              • $begingroup$
                I agree with TPM for a lot of reasons, unfortunately the data was already in TPM. Can you explain more about how read counts are useful to determine shot noise and statistical significance? Thanks
                $endgroup$
                – gc5
                1 hour ago


















              • $begingroup$
                I agree with TPM for a lot of reasons, unfortunately the data was already in TPM. Can you explain more about how read counts are useful to determine shot noise and statistical significance? Thanks
                $endgroup$
                – gc5
                1 hour ago
















              $begingroup$
              I agree with TPM for a lot of reasons, unfortunately the data was already in TPM. Can you explain more about how read counts are useful to determine shot noise and statistical significance? Thanks
              $endgroup$
              – gc5
              1 hour ago




              $begingroup$
              I agree with TPM for a lot of reasons, unfortunately the data was already in TPM. Can you explain more about how read counts are useful to determine shot noise and statistical significance? Thanks
              $endgroup$
              – gc5
              1 hour ago











              2












              $begingroup$

              What I have generally done in the past is to process the data using voom in the limma package for bulk RNASeq. Inside voom you can call for different normalization methods to be used - "TMM" works fine for me and, is advocated by many in the field.



              voom will output an object containing the normalized expression values in a log2 scale, which, also in my experience, has worked out just fine for calculating log fold changes.



              Check out this link for more info on the package as well as normalization methods: https://www.bioconductor.org/packages/devel/workflows/vignettes/RNAseq123/inst/doc/limmaWorkflow.html
              It is a very thorough introduction to the package and all of its capabilities.



              Good luck!






              share|improve this answer









              $endgroup$


















                2












                $begingroup$

                What I have generally done in the past is to process the data using voom in the limma package for bulk RNASeq. Inside voom you can call for different normalization methods to be used - "TMM" works fine for me and, is advocated by many in the field.



                voom will output an object containing the normalized expression values in a log2 scale, which, also in my experience, has worked out just fine for calculating log fold changes.



                Check out this link for more info on the package as well as normalization methods: https://www.bioconductor.org/packages/devel/workflows/vignettes/RNAseq123/inst/doc/limmaWorkflow.html
                It is a very thorough introduction to the package and all of its capabilities.



                Good luck!






                share|improve this answer









                $endgroup$
















                  2












                  2








                  2





                  $begingroup$

                  What I have generally done in the past is to process the data using voom in the limma package for bulk RNASeq. Inside voom you can call for different normalization methods to be used - "TMM" works fine for me and, is advocated by many in the field.



                  voom will output an object containing the normalized expression values in a log2 scale, which, also in my experience, has worked out just fine for calculating log fold changes.



                  Check out this link for more info on the package as well as normalization methods: https://www.bioconductor.org/packages/devel/workflows/vignettes/RNAseq123/inst/doc/limmaWorkflow.html
                  It is a very thorough introduction to the package and all of its capabilities.



                  Good luck!






                  share|improve this answer









                  $endgroup$



                  What I have generally done in the past is to process the data using voom in the limma package for bulk RNASeq. Inside voom you can call for different normalization methods to be used - "TMM" works fine for me and, is advocated by many in the field.



                  voom will output an object containing the normalized expression values in a log2 scale, which, also in my experience, has worked out just fine for calculating log fold changes.



                  Check out this link for more info on the package as well as normalization methods: https://www.bioconductor.org/packages/devel/workflows/vignettes/RNAseq123/inst/doc/limmaWorkflow.html
                  It is a very thorough introduction to the package and all of its capabilities.



                  Good luck!







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 2 hours ago









                  h3ab74h3ab74

                  836




                  836























                      0












                      $begingroup$

                      You have only two samples?



                      You aren't going to be able to draw strong conclusions from that no matter what you do. Clever statistics don't work without replicates.






                      share|improve this answer









                      $endgroup$


















                        0












                        $begingroup$

                        You have only two samples?



                        You aren't going to be able to draw strong conclusions from that no matter what you do. Clever statistics don't work without replicates.






                        share|improve this answer









                        $endgroup$
















                          0












                          0








                          0





                          $begingroup$

                          You have only two samples?



                          You aren't going to be able to draw strong conclusions from that no matter what you do. Clever statistics don't work without replicates.






                          share|improve this answer









                          $endgroup$



                          You have only two samples?



                          You aren't going to be able to draw strong conclusions from that no matter what you do. Clever statistics don't work without replicates.







                          share|improve this answer












                          share|improve this answer



                          share|improve this answer










                          answered 1 hour ago









                          swbarnes2swbarnes2

                          47114




                          47114






























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