During meiosis, genetic recombination may occur more than once through the process of ____________________, resulting in an increase in genetic variability.

Crossing-over is a phenomenon that occurs in the Prophase stage of meiosis I. Two chromosomes of a homologous pair comes together in a process called SYNAPSIS to form a TETRAD structure. While the chromosomes synapses, breaks occur at corresponding points in the non-sister chromatids i.e in one chromatid of each chromosome. Since the chromosomes are homologous, breaks at specific points mean that the segments that are broken off contain specific genes i.e. alleles. The broken sections are then exchanged between the chromosomes to form complete new units, and each new recombined chromosome of the pair can go to a different daughter sex cell.

In meiosis, the maternal and paternal chromosomes can be shuffled into daughter cells in many different combinations. The resulting chromosomes are not entirely maternal, neither are they entirely paternal. This ensures genetic variation in sexually reproducing organisms.