Recombination

Linkage is determined by the behaviour of homologous chromosomes during meiosis. When these pair with one another, some chromosome segments are exchanged between them, resulting in the creation of daughter chromosomes which are composed of segments from each parent. This process is called crossing-over, or recombination.

Here, 2 homologous chromosomes have exchanged genetic material via recombination.

Image: Wikipedia, the free encylopedia