The Melanesian Gerbich Negative Allele Of Glycophorin C Has A Local Origin
The Gerbich negative allele of the erythrocyte surface protein glycophorin C (GYPC) is extremely rare except in some Pacific populations, where it has been controversially associated with protection against malaria. A rapid assay for the Gerbich negative allele using a single PCR per individual was developed and used to screen samples from selected populations within and outside of Papua New Guinea. SNP variation in the GYPC gene was assessed and used to infer haplotypes for Gerbich negative and wildtype alleles using the program PHASE. There is little variation linked to Gerbich negative alleles. However, wildtype alleles whose SNP variation is identical to the most common Gerbich negative haplotype are present in high frequencies in some PNG populations where Gerbich negative is rare or absent. Moreover, these particular wildtype alleles were not found in populations from outside of PNG, nor in a PNG population where Gerbich negative was common. This suggests that the original Gerbich negative mutation arose within PNG, spread to its current distribution, and was then driven to locally high frequencies by locally acting factors.