Spatial efficiency/specificity patterns and conservation. (A) Definition of spatial efficiency/specificity patterns. Ortholog gene pairs with identical numbers of conserved polyadenylation sites are considered. A conserved pattern is defined as a series of sites between two orthologous genes, where each site bares the same properties (major/minor or broad/narrow) as its orthologous counterpart (e.g. gene X). All other patterns are defined as non-conserved (e.g. gene Y). (B) Relationship between tandem poly(A) site spatial patterns and conservation. The first row shows different patterns in which one major site is conserved. The second row shows different patterns in which two sites are conserved. Numbers of human genes ("h") and mouse genes ("m") displaying each pattern are shown. Circled numbers indicate ratio of patterns in second row over patterns in first row.