The same correlation was not observed for the budding yeast S. cerevisiae,whose ribosomes, like other eukaryotes, do not contain an anti-SD (aSD) site.As predicted by a model in which the interaction between mRNA and the aSD site of the16S rRNA is the source of pausing, the predicted hybridization free energy of ahexanucleotide to the aSD sequence is a strong predictor of its average downstreamrib