Most lncRNA erythroid genes are not cross-expressed in mice and humans. (A) Boxplots showing the extent to which mature RNAs overlap with PhastConsElements, reflecting DNA sequence conservation in multispecies alignments. The degree of overlap for lncRNA genes is greater than random, but lower than for coding genes. (B) PhastConsElement overlap of lncRNA genes subclassified by orientation relative to coding genes (see Figure 1G). (C) Percentages of mouse erythroid genes transmapping to the human genome and expressed in the human erythroblasts (combined transcriptomes of 5 maturational stages, as detailed in the text). Less than 20% of murine erythroid lncRNA genes are expressed in humans despite identified transmapping orthologous regions for most. (D) Percentages of human erythroid genes transmapping to the mouse genome and expressed in mouse erythroblasts showing low levels of conserved lncRNA expression. HS, high stringency; LS, low stringency.