DNA chips, also known as microarrays, contain thousands of genes arranged on a small chip. Each gene occupies its own spot on the chip. By introducing genetic samples onto the chip, researchers can determine which genes are most active and gain insights into how genetics affect traits and diseases. Emerging nanotechnologies allow the creation of even smaller DNA chips with higher resolution using techniques like dip pen nanolithography and electrochemical sensing. These nano-scale DNA chips have the potential to revolutionize the study of genomics and functional genomics.