All gene-sized DNA molecules in four species of hypotrichs have the same terminal sequence and an unusual 3' terminus.

Abstract

In hypotrichous ciliates, all macronuclear DNA is in the form of low MW molecules with an average size of .apprxeq. 2200 base pairs. Total macronuclear DNA from 4 hypotrichs had inverted terminal repeats by direct sequence analysis. In Oxytricha nova, Oxytricha sp. and Stylonychia pustulata, this terminal sequence is described. In Euplotes aediculatus, the sequence is similar but differs in the lengths of the duplex region (28 base pairs) and of the putative 3'' extension (14 base pairs). In Euplotes, a 2nd common sequence of 5 base pairs occurs internal to the terminal repeat and a 17-base-pair heterogeneous region. The length of the terminal repeat sequence for O. nova was confirmed in cloned macronuclear DNA molecules.