BIOINFORMATIX LEARNING PATH

Become an RNA-Seq Analyst

Learn how to transform raw RNA sequencing reads into differential expression results, visualizations and biological interpretation.

01FASTQRaw reads
02COUNTSExpression
03DEGsChange
04INSIGHTMeaning

PATH ORIENTATION

Who This Path Is For

Build practical bulk RNA-Seq analysis skills before moving into advanced transcriptomics.

  • Bioinformatics students
  • Molecular biology researchers
  • Transcriptomics researchers
  • Graduate students
  • NGS analysts
  • Learners interested in gene expression

FROM RAW READS TO BIOLOGICAL INSIGHT

Follow the Expression Analysis Workflow

Each step changes the representation of the data and answers a different analytical question.

  1. 01Biological Question
  2. 02RNA
  3. 03Sequencing
  4. 04FASTQ
  5. 05Quality Control
  6. 06Alignment / Quantification
  7. 07Gene Counts
  8. 08Normalization
  9. 09Differential Expression
  10. 10Visualization
  11. 11Functional Analysis
  12. 12Biological Interpretation

CORE BULK RNA-SEQ PATH

Build the Analysis From Question to Interpretation

Ten connected stages turn transcriptomics concepts into a complete, reproducible expression analysis.

01FOUNDATION

Understand the Transcriptome

RNA-Seq measures a dynamic collection of transcripts. Learn what is being counted before deciding how to analyze it.

GENE
ISOFORM A
ISOFORM B
  • Gene expression
  • Transcripts
  • mRNA
  • Exons
  • Introns
  • Isoforms
  • Transcriptome
02DESIGN

Design the Comparison Before Analyzing Data

Good computational analysis cannot rescue a fundamentally poor experimental design. Define the comparison and sources of variation before sequencing.

CONDITION AA1A2A3
VS
CONDITION BB1B2B3
Biological Replicates

Measure biological variation, not just technical repetition.

Controls

Make the intended comparison interpretable.

Batch Effects

Technical structure can resemble biology.

Confounding

A factor must not perfectly overlap the condition.

03RAW DATA

Inspect Raw RNA-Seq Data

FASTQ records contain RNA-derived sequencing reads and per-base quality information. Paired-end data provides two reads for each sequenced fragment.

@sample_A_read_01
GATCGTACGTTGCA
+
IIHHHFFFGGGGEE

What to Check

  • Paired-end readsMatching R1 and R2 files
  • Quality scoresConfidence in each base
  • Read depthTotal reads per sample
04QUALITY CONTROL

Evaluate Read Quality

FastQC helps diagnose possible issues before alignment or quantification. Review patterns across all samples rather than judging one metric in isolation.

PER-BASE QUALITY
  • PASSQuality profiles
  • CHECKAdapter content
  • PASSGC distribution
  • REVIEWDuplication
05QUANTIFICATION

Choose an Alignment or Quantification Strategy

Both approaches estimate expression, but they represent reads and transcripts differently. The appropriate strategy depends on the question.

ALIGNMENT-BASED
  1. FASTQ
  2. STAR / HISAT2
  3. BAM
  4. featureCounts
  5. Count Matrix

Creates genomic alignments, then assigns reads to annotated features.

QUASI / PSEUDO-ALIGNMENT CONCEPT
  1. FASTQ
  2. Transcript Quantification
  3. Abundance Estimates

Estimates transcript abundance without producing conventional genomic alignments.

06EXPRESSION TABLE

Read a Gene Count Matrix

Genes are rows, samples are columns and counts are measurements. Raw counts cannot be compared directly without considering sequencing depth and composition.

Example raw count matrix
GeneA1A2A3B1B2B3
TP53120128119684701659
MYC902875911240263251
GAPDH530548521560553571
IL6182521740795762
ROWS = GENESCOLUMNS = SAMPLESVALUES = COUNTS
07NORMALIZATION

Make Samples Comparable

Normalization accounts for technical differences such as library size and composition effects. DESeq2 conceptually estimates sample-specific size factors rather than simply dividing every count by total reads.

RAW LIBRARIESA1A2B1B2
NORMALIZED SCALEA1A2B1B2
08DIFFERENTIAL EXPRESSION

Identify Genes That Change Between Conditions

Differential expression combines effect size and statistical evidence. Interpret both, along with study design and biological context.

log2 fold change
Direction and magnitude of expression change.
p-value
Evidence under the statistical model for one test.
adjusted p-value
Controls false discoveries across many gene tests.
up / downregulated
Higher or lower expression in the defined comparison.
09VISUALIZATION

Use Visuals to Ask Specific Questions

RNA-Seq visualizations are diagnostic and explanatory tools. Choose each plot for the question it answers.

PCA

Do samples separate by condition or another source of variation?

Sample Clustering

Which samples have similar global expression profiles?

Heatmap

How do selected genes vary across samples?

Volcano Plot

Which genes combine large changes with strong evidence?

MA Plot

Does expression change depend on average abundance?

Expression Plot

How does one gene vary across conditions and replicates?

10INTERPRETATION

Move From a DEG List to Biological Meaning

A DEG list is not the end of an RNA-Seq analysis. Functional analysis asks whether genes share biological processes, pathways or coordinated functions.

DEG LIST284 genes
GENE SETSGO + pathways
ENRICHMENTShared functions
INTERPRETATIONBiological model
  • GO enrichment
  • Pathway analysis
  • KEGG concept
  • Gene sets
  • Biological context

AFTER THE CORE PATH

Where Advanced Transcriptomics Begins

These are optional directions after bulk RNA-Seq fundamentals, not requirements for a beginner analyst.

BULKRNA-SEQ
01

lncRNA

Long non-coding transcript analysis

02

miRNA

Small RNA expression and targeting

03

Alternative Splicing

Isoform and exon usage changes

04

PSI

Percent spliced-in analysis

05

Single-Cell RNA-Seq

Expression at cellular resolution

WORKFLOW TOOLBOX

Tools Organized by Analysis Stage

Learn why a tool is used and what it produces. You do not need every available tool.

ENVIRONMENT

Linux

Files, commands and reproducible execution.

RAW QC

FastQC

Quality profiles and read diagnostics.

ALIGNMENT

STAR + HISAT2

Splice-aware mapping to a genome.

COUNTING

featureCounts

Assign aligned reads to annotated genes.

ANALYSIS

R + DESeq2

Normalization and differential expression.

VISUALIZATION

ggplot2

Clear statistical and expression graphics.

ECOSYSTEM

Bioconductor

RNA-Seq data structures and methods.

INTERPRETATION

Enrichment Tools

GO, pathways and gene-set context.

PROJECT PROGRESSION

Build a Complete RNA-Seq Portfolio

Each project adds a new data transformation until you can complete an end-to-end public dataset analysis.

  1. 01
    PROJECT 1

    RNA-Seq Quality Control

    Assess FASTQ quality across samples and write justified recommendations.

  2. 02
    PROJECT 2

    FASTQ to Gene Count Matrix

    Follow alignment and counting to produce a sample-by-gene table.

  3. 03
    PROJECT 3

    Differential Expression Analysis

    Normalize counts, fit a comparison and interpret DEG statistics.

  4. 04
    PROJECT 4

    PCA + Heatmap + Volcano Plot

    Create a coherent visual story from sample structure to gene changes.

  5. 05
    PROJECT 5

    Functional Enrichment

    Connect gene-level results with processes and pathways.

  6. 06
    CAPSTONE

    Complete Public RNA-Seq Dataset Analysis

    Frame a biological question and deliver a reproducible analysis with interpretation.

    • Workflow documentation
    • QC summary
    • Count matrix
    • PCA
    • DEG results
    • Volcano plot
    • Heatmap
    • Enrichment results
    • Biological interpretation
    • README

LEARN WITH BIOINFORMATIX

Training Connected to the Workflow

Use structured courses to support practical analysis and the next appropriate transcriptomics direction.

CORE BULK RNA-SEQHands-on RNA-Seq Analysis: From FASTQ to DEGsView course
ADVANCED TRANSCRIPTOMICSLearn Advanced Transcriptomics: lncRNA, miRNA & PSI-Seq Data AnalysisView course
SINGLE CELLLearn Single Cell RNA-Seq Data Analysis Using R and PythonView course
COMPUTATIONAL FOUNDATIONLearn Bioinformatics Data Analysis: Master Python, Linux and R ScriptingView course

SELF-ASSESSMENT

RNA-Seq Readiness Check

Mark skills you can explain or perform without step-by-step guidance. Your progress is stored only in this browser.

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RNA-Seq readiness skills

FROM READS TO MEANING

Build an RNA-Seq Analysis You Can Explain and Reproduce

Start with a clear biological question, respect the experimental design and carry the evidence through every step to interpretation.

Explore RNA-Seq TrainingStart a Public Dataset ProjectExplore Advanced Transcriptomics