Fig. 11.

Evidence that the GKN3 locus is not expressed. Expression levels of GKN3 compared with the other gastrokines, GKN1 and GKN2, as well as 2 mucous neck cell-specific transcripts TFF2 and MUC6 (A). Expression was analyzed by RNA sequencing, and values are shown as FPKM, fragments per kilobase of exon per million fragments mapped. All samples were from gastric resections from Nicaraguan patients and genotyped, using restriction fragment length polymorphism (RFLP) analysis to be homozygous for STOP alleles (A/A) at SNP rs10187256. No GKN3 expression was detected in 17 other Nicaraguan patients, though we were not able to genotype those patients (not shown). RFLP of genomic DNA from 10 randomly selected patients whose stomachs were resected for gastric cancer in St. Louis (B). Half are homozygous for the STOP (A/A) alleles and half heterozygous (A/G). No message or protein was detected from any of the stomachs of these patients (not shown). Distribution of alleles at this SNP site in the 1000 Genomes data is depicted in C. The G allele and G/G genotype are most common in African populations (YRI, LKW, ASW). The last two columns represent the RFLP data from St. Louis (STL) and Nicaragua samples (NCG) analyzed to date.