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. Author manuscript; available in PMC: 2015 May 18.
Published in final edited form as: Clin Transl Sci. 2009 Oct;2(5):355–360. doi: 10.1111/j.1752-8062.2009.00148.x

Figure 1. The GNAS gene complex located at 20q13.3 consists of 13 exons that encode the signaling protein Gαs.

Figure 1

Upstream of exon 1 are three alternative exons, labeled exon 1A, XLαs, and NESP55. These three alternative first exons are spliced to exons 2–13 to produce unique transcripts. NESP55 is transcribed exclusively from the maternal allele; XLαs and exon 1A are transcribed exclusively from the paternal allele. RT-PCR using an upstream primer specific for Gαs, XLαs, and NESP55 first exons of GNAS and a common downstream primer within exons 6, 8, and 13 of GNAS enabled us to genotype the alleles using a highly variable single nucleotide polymorphism in codon 131 (T/C) of exon 5, codon 185 (T/C) of exon 7, and codon 371 (T/C) of exon 13. The primers are indicated by thin black arrows; direction of transcription are indicated by thick arrows (thick gray arrows indicate transcription from maternal allele; black arrows indicate transcription from paternal allele).