Identifying tammar IGF2 transcription start sites.
5′-RACE amplification was performed on (A) liver and (B) placenta RNA samples. (A) Three bands first identified in the liver (black arrows) were visible in both tissue types. (B) Additional exon 1B transcription start sites (TSS) were identified in the placenta. (C) Aligning the cloned products to the gDNA sequence identified the location of each of the non-coding exons 1A, 1B and 1C (white boxes) in relation to the coding exons 2, 3 and 4 (black boxes) followed by an untranslated region of unknown length (dashed box). TSSs are indicated by turned arrows. Two single nucleotide polymorphisms (black triangles) identified in the untranslated region were used for imprint analysis (snp1 and snp2). Diagram is not to scale.