Genomic structure and sequence of the G1m allotypes. In the upper graph, the schematic structure of the immunoglobulin heavy constant gamma 1 (IGHG1) gene in chromosome14 is shown with white rectangles for the CH exons and a black rectangle for the hinge (H) sequence. Below, the IGHG1 sequences that were amplified to genotype rs1071803 (for G1m17/G1m3) and rs11621259 (for G1m1/nullG1m1) are shown with the aligned sequences that could be co-amplified with the same primers according to Blastn (megablast, default settings). IGHG3, IGHG2 and IGHG4 code for the heavy chains of IgG3, IgG2 and IgG4, respectively, while IGHGP is a pseudogene. Exon sequences are framed in boxes. The three nsSNPs encoding the allotypes are in bold following the International Union of Pure and Applied Chemistry nomenclature: R for the G/A alleles at rs1071803; M for the C/A alleles at rs11621259; and K for the G/T alleles at the other nsSNP encoding the G1m1/nullG1m1 allotype. Primers and minisequencing probes are underlined. nsSNP, non synonymous single nucleotide polymorphisms.