The insulin-like growth factor 2 gene in mammals: Organizational complexity within a conserved locus
Detailed views of 10 mammalian H19 genes for which genomic data are relatively complete; exons are boxes, and introns and flanking DNA are horizontal lines. P1 and P2 depict the two gene promoters found in several primates. P denotes the gene promoter in other species. Bent arrows indicate different transcription start sites directed by human P2 and straight vertical arrows depict locations of alternative polyadenylation sites. The Tasmanian (Tas) devil H19 gene was mapped by similarity with the wallaby gene; the lighter gray portion of Tasmanian devil exon 5 depicts an area that could not be characterized because of poor quality DNA sequence (see Table 2). A scale bar is shown.