Genome-wide evidence for selection acting on single amino acid repeats

Low complexity and homopolymer sequences within coding regions are known to evolve rapidly. While their expansion may be deleterious, there is increasing evidence for a functional role associated with these amino acid sequences. Homopolymer sequences are thought to evolve mostly through replication slippage and, therefore, they may be expected to be longer in regions with relaxed selective constraint. Within the coding sequences of eukaryotes, …