Copy number variation at the NCF1 locus. a) The ratio of NCF1 and NCF1Ψ genes as determined by pyrosequencing the GT deletion ([GT]/[GTGT]). b) The percentage of NCF1, NCF1B and NCF1C copies in the gene pool of each population. c) The average copy numbers of NCF1, NCF1B and NCF1C in each individual (mean ± SD). Three independent experiments were performed in duplicates. P values are indicated.