A segment of the gene for PAH, showing positions of some deletions that may be associated with the disease PKU. The CTT deletion (shown in reverse orientation) removes an amino acid whose column has six distinct letters and in that sense is not well conserved. The nucleotide symbol “N” represents an unsequenced base, and “=” indicates that at this location in the aligning species there is a sequence of bases of such different length and/or sequence composition that it cannot be reliably aligned. The two conservation tracks indicate that the deleted position is not well conserved among all vertebrates, but is fairly well conserved within mammals. chr12:101,761,637–101,761,687.
