Transfer RNA: Evidence for decreasing size variation during evolution

Summary Electrophoresis of the total transfer RNA fraction from six different sources:E. coli, brewer's yeast, wheat embryo, carp liver, rabbit liver and rat liver, was performed in a 20% polyacrylamide gel. Clear evidence was demonstrated for a decreasing tRNA size variation during evolution. Thus, two parameters seem to be involved in maintaining the necessary degree of tRNA variability: mainly tRNA size variation in lower organisms, and increased tRNA modification in higher organisms.This paper is dedicated to Prof. A. Butenandt on the occasion of his 70th birthday.