This document discusses karyotyping, which involves pairing and ordering chromosomes to provide a genome-wide snapshot of an individual. Karyotypes can reveal chromosomal abnormalities like changes in number (e.g. Down syndrome) or structure (e.g. deletions, duplications). Clinical cytogeneticists analyze human karyotypes to detect genetic anomalies involving large amounts of DNA. Karyotyping is becoming a diagnostic tool for birth defects, genetic disorders, and cancers.