Size differences of large ribosomal RNA in vertebrates

By using a modification of acrylamide gel electrophoresis in the presence of 95 per cent formamide it is shown that real differences exist in the size of rRNA of the large ribosomal subunit (LrRNA) in vertebrates. Comparative studies on fractionation of LrRNA's in unfolded state (polyacrylamide-formamide gel) and when the conformation of RNA is preserved (agar gel) revealed that LrRNA from different classes of vertebrates show different conformations.