ACKR1 alleles at 5.6 kb in a well-characterized renewable FDA reference panel for standardization of blood group genotyping.

Abstract The glycoprotein encoded by the ACKR1 gene expresses the Duffy blood group antigens and is a receptor for malaria parasites. We recently described 18 long-range ACKR1 alleles in an autochthonous population of a malaria endemic region. Extending this work, we sequenced the gene in a 53 sample repository established by the FDA as reference reagents for blood group genotyping. The FDA samples have been characterized for 19 genes; however, long-range haplotype information for these genes, including ACKR1, was lacking. We used a hybrid approach, novel for this type of genes, to characterize ACKR1 by combining 2 next generation sequencing technologies, the short-read Illumina sequencing and the long-read GridION nanopore sequencing. The expedient integration of data from both next generation sequencing systems was necessary and sufficient to allow us accurately determining all 25 long-range ACKR1 alleles found in such 53 samples. All 25 alleles identified in our current FDA cohort were novel and, unexpectedly, none had been observed among the 18 alleles of our previous study. The alleles will be useful for validation, calibration and proficiency testing of red cell genotyping. The lack of any overlap between the ACKR1 alleles in the 2 studies document differences in mutation rate and recombination frequency among populations. The exact haplotype and their interethnic or inter-population dissimilarities can influence disease susceptibility and therapy.