Figure 2:

Short poly(A) tails are associated with highly expressed, well-translated transcripts. These shortened tails occur at discrete lengths that have a phasing pattern matching the footprint of serial binding of cytoplasmic poly(A) binding protein. Longer tails do not show this phasing and have less well-defined tails. In somatic cells, short tailed transcripts tend to have high codon optimality and long half lives.