Log2FoldChange to Percentage Explained! скачать в хорошем качестве

Log2FoldChange to Percentage Explained!

A Tutorial on Converting Log2 Fold Change to Percentage Change In RNA-sequencing analysis, we use log2 fold change (Log2FC) to quantify how much a gene's expression differs between two experimental conditions. But interpreting log2 values can be difficult. Converting log2FC to percentage change makes the gene expression differences more interpretable. Log2FC indicates how many fold higher or lower a gene's expression is in the test group relative to the control group. A positive Log2FC means the gene is upregulated or higher expressed in the test group. A negative Log2FC means the gene is downregulated or lower expressed compared to control. To convert between log2FC and percentage change, we need to understand some mathematical relationships: The log2 scale is based on powers of 2. Each unit increase in log2FC corresponds to a doubling. A log2FC of 1 equals a 2-fold linear change. A log2FC of 2 is a 4-fold linear change. And so on for other log2 values. We can convert the log2 scale to a linear scale using the power function 2^Log2FC. Once in linear scale, we can calculate the proportional change relative to control. For positive Log2FC: 2^Log2FC transforms the log2 value to the linear fold change Subtracting 1 gives us the proportional increase over control Multiplying by 100 converts to percentage Percentage Increase = (2^Log2FC - 1) x 100 For example, Log2FC of 1 = 2^1 = 2 fold increase → (2 - 1) = 1 → 1 x 100 = 100% increase For negative Log2FC: 2^-Log2FC transforms the log2 value to the linear fold decrease Subtracting from 1 gives us the proportional decrease relative to control Multiplying by 100 converts to percentage Percentage Decrease = (1 - 2^-Log2FC) x 100 For example, Log2FC of -2 = 2^-2 = 0.25 fold decrease → (1 - 0.25) = 0.75 → 0.75 x 100 = 75% decrease In bioinformatics, these formulas allow us to quickly convert the log2FC values from RNA-seq differential expression analysis into more interpretable percent changes in either direction. Understanding the mathematical basis helps gain intuition for how log2 scales relate to proportional increases and decreases.