Reassortment is the mixing of the
genetic material of a species into new combinations in different individuals. Several different processes contribute to reassortment, including assortment of chromosomes, and
chromosomal crossover. It is particularly used when two similar
viruses that are infecting the same cell exchange genetic material. In particular, reassortment occurs among
influenza viruses, whose genomes consist of eight distinct segments of RNA. These segments act like mini-chromosomes, and each time a flu virus is assembled, it requires one copy of each segment.