Genomics Guide: The Essential Guide – Exploring the Science of Genomes

The human genome contains approximately 3.2 billion base pairs of DNA distributed across 23 pairs of chromosomes, encoding roughly 20,000 to 25,000 protein-coding genes. However, protein-coding sequences represent only about 1.5% of the genome, with the remainder consisting of regulatory sequences, introns, repetitive elements, and other non-coding DNA that was once dismissed as "junk DNA" but is now recognized as playing crucial roles in genome function and regulation.

The structure of genomes reveals remarkable complexity and organization that reflects billions of years of evolutionary refinement. Genes are not randomly distributed but are organized into functional clusters, regulatory domains, and chromosomal territories that influence their expression and function. The three-dimensional organization of chromatin within the nucleus creates additional layers of regulation that determine which genes are accessible for transcription under different cellular conditions.