CONSERVATION OF STRUCTURE OF RIBOSOMAL RNA DURING EVOLUTION

Limited digestion of ribosomal RNA with T1 ribonuclease results in breakage of the polynucleotide chain at specific loci. The fragments are separated according to size with good resolution by polyacrylamide gel electrophoresis. The electrophoretic pattern is characteristic of the type of RNA and provides an index of the similarity or differences between closely related species. In this work we have examined the ribosomal RNA from several mammalian and microbial species. The results warrant the following general conclusions: (1) the structure of ribosomal RNA has differentiated appreciably in the course of evolution; (2) the over-all structure as opposed to the nucleotide sequence tends to be conserved during evolution; (3) there is no evidence of heterogeneity in ribosomal RNA population from a given species. © 1969.