Gamete cells are produced to transmit genetic information from parents to their progeny. The cells are formed by a special process of cell division, called meiosis, which results in the halving of the chromosome number in each parental gamete so that the full complement can be restored when sperm and ovum unite. First , the chromosomes appear in the nucleus of the cell and then duplicate. Like chromosomes link together and exchange different section of their length before separating and lining up across the center. They are pulled to opposite poles and eventually two cells are formed, each one containing one member of each pair of chromosomes from the original cell. Then a second division begins and, in the same way, the chromosomes arrange themselves across the center of the nucleus. This time one-half of each chromosome, a chromatid, moves to the poles of the nucleus. Within the four cells that are formed each chromatid will eventually replicate to form a chromosome and each gamete cell will contain half the original chromosome number.