Biology
Natural Selection Acting on Non-Coding Regulatory DNA
Quick fact
In the threespine stickleback fish, a single mutation in a non-coding enhancer region controls whether pelvic spines develop, allowing freshwater populations to lose their spines in just a few thousand years—a classic example of natural selection acting on regulatory DNA rather than on the gene itself.
Why this is interesting
You might think evolution works by changing genes themselves—but often the real action is in the 'switches' that turn genes on and off. What if a tiny change in a regulatory region, not a gene, could make a species grow a new trait?