Adolescence in Tetrahymena thermophila.

The development of sexual maturity in Tetrahymena thermophila has been shown to include an intermediate stage, adolescence, during which cells are capable of mating with mature cells but not other adolescent cells. When the progeny of successfully mated cells are grown logarithmically and tested frequently for the ability to mate, they are unable to form mating pairs for about 65 generations. This period is known as immaturity. During the next stage, the progeny pair with mature cells but not with other adolescent cells despite the presence of complementary mating types. Adolescence persists for 20-25 generations before the cells attain maturity, which is defined as the ability to mate with any cell of different mating type. Once paired with mature cells, adolescents successfully complete conjugation. Cytological preparations show that both members of the pair undergo meiosis and form macronuclear anlagen. The proteins synthesized during a mating between adolescents and mature cells are similar to those synthesized during a mating between mature cells as determined by two-dimensional gel analysis. Both the adolescent cell and the mature partner contribute genetic markers to the progeny.