What is fold change? What is logFC?
What is fold change?
Fold change is a metric that expresses the extent of change between two measurements. In gene expression analysis, such as microarray or RNA-Seq analysis, it refers to the ratio of expression between samples or between groups
What is logFC?
Fold change converted to a logarithmic scale (log fold change, log2 fold change) is sometimes denoted as logFC. In many cases, the base is 2.
Examples of Fold Change / logFC
For example, if the average expression level is 100 in the control group and 200 in the treatment group, the fold change is 2, and the logFC is 1.
| Gene Name | Average Expression Level in the Control Group | Average Expression Level in the Treatment Group | fold change | logFC |
| Gene A | 100 | 200 | 2 | 1 |
| Gene B | 100 | 400 | 4 | 2 |
| Gene C | 200 | 100 | 0.5 | -1 |
In gene expression analysis, such as microarray or RNA-Seq analysis, figures such as Volcano plots and MA plots are commonly drawn. LogFC corresponds to the x-axis in a Volcano plot and to the y-axis in an MA plot.
Example of a Volcano Plot
Example of an MA Plot
RNA-Seq Data Analysis Software
For those who don't have the time to study analysis methods or lack a high-spec computer necessary for the analysis, please consider using our RNA-Seq data analysis software.
Starting with either raw RNA-Seq data (FASTQ files/public data) or expression tables (CSV/TSV files), users can perform gene expression quantification, identification of differentially expressed genes, gene ontology(GO) analysis, pathway analysis, as well as drawing volcano plots, MA plots, and heatmaps.