IDENTIFICATION AND ANALYSIS OF TETRAHYMENA-PYRIFORMIS 26S RIBOSOMAL-RNA SEQUENCES DIFFERING IN EVOLUTIONARY CONSERVATISM

Domains differing in evolutionary conservatism were identified in Tetr ahymena pyriformis 26S rRNA. A highly conservative 1212-bp fragment of ?: pyriformis DNA was cloned. This fragment may be used as a probe in blot hybridization analysis of rDNA structural organization in organi sms of various origin, from protozoa to mammals. Superconservative and hypervariable domains were characterized. The former can be recommend ed as primers in PCR studies of rRNA of a broad variety of species whi le the latter may be employed as species-specific primers.