Quantitative Trait Locus (QTL) mapping is a statistical method used in genetics to identify regions of the genome that are associated with specific quantitative traits, such as height, weight, or disease susceptibility. By studying the genetic variation among individuals and correlating it with variation in their traits, researchers can identify the genetic markers that are linked to the trait of interest. QTL mapping is commonly used in plant and animal breeding to identify the genetic basis of complex traits and to facilitate the development of improved strains or breeds. This technique is also used in human genetics to study the genetic basis of diseases and other traits. Overall, QTL mapping provides valuable insights into the genetic architecture of complex traits and can help researchers understand the underlying biological mechanisms that contribute to variation in phenotypic traits.