A linkage map is a genetic tool used to determine the relative positions of genes on a chromosome. It is created by analyzing the frequency of recombination between different genes during meiosis. The closer two genes are to each other, the less likely they are to be separated during this process, allowing scientists to estimate their distances in terms of map units or centimorgans. Linkage maps are essential for understanding genetic traits and inheritance patterns in organisms, including humans, plants, and animals. They help researchers identify genes associated with specific diseases or characteristics, facilitating advancements in fields like genetics, breeding, and medicine.