THE PROCESSING OF MACRONUCLEAR DNA-SEQUENCES DURING MACRONUCLEAR DEVELOPMENT OF THE HYPOTRICHOUS CILIATE STYLONYCHIA-LEMNAE

The organization of two macronuclear DNA sequences in the polytene chr omosomes of the hypotrichous ciliate Stylonychia lemnae and their proc essing from the micronucleus via the polytene chromosome stage up to t he macronucleus was analyzed. The overall organization of these sequen ces in the polytene chromosomes resembles that described for the micro nucleus of other hypotrichous ciliates, i.e. they are interrupted by i nternal eliminated sequences and not associated with telomeric sequenc es. The spacer region between the genes is bordered by direct repeats and inverted repeats are found at the termini of macronuclear sequence s and in the spacer region. The organization of these macronuclear DNA sequences in the micronucleus was analyzed by polymerase chain reacti ons. The results obtained show that in the sequences analyzed no DNA r eorganization occurs during polytene chromosome formation.