Most wild type Tetrahymena have a macronucleus and a
micronucleus. The micronucleus (mic), seen here, is essentially
nonfunctional during interphase. Its function is to replicate and pass
a complete copy of the genome to each daughter cell and to give rise
to a new macronucleus following sexual reproduction. Many laboratory
strains, unlike strain W which is shown here, have lost their
micronucleus and seem to be able to live indefinitely without a
micronucleus, however, they can no longer undergo meiosis and sexual
reproduction. av, autophagosome. EM taken on 4/8/65 by R. Allen
with RCA EMU3F TEM. Neg. 9,100X. Bar = 0.5µm.
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