Linkage disequilibrium

Linkage disequilibrium is the tendency for certain genetic variants to be inherited together more often than would be expected by random chance, because they are located close to each other on a chromosome. Think of it like two neighboring houses in a town—if one house has a red door, the nearby house is more likely to have a red door too, simply because they're next to each other and less likely to have been separated over time. Scientists use this concept to map genes, understand population history, and identify DNA regions associated with diseases without having to test every single genetic variant.