What is target identification and validation in drug discovery?

Target identification is the process of finding disease-relevant biological molecules (usually proteins) that can be modulated by drugs. Approaches include: genomics and transcriptomics (identifying disease-associated genes), proteomics (protein expression differences), genetic studies (GWAS, Mendelian diseases), pathway analysis, and literature mining. Target validation confirms the target's role in disease and druggability through: genetic knockdown/knockout (siRNA, CRISPR), chemical probes, animal disease models, biomarker studies, and analysis of human genetic data (loss-of-function variants). A good target should be: causally linked to disease, druggable (accessible binding site), selective (avoid off-target effects), and have a measurable biomarker. Poor target selection is a major cause of drug development failure.