CHIT1 and ancylostomiasis: The aims of the current study were (1) to investigate associations between CHIT1 genotype and human hookworm infection in an endemic population from Madang Province, Papua New Guinea and (2) to investigate evidence for directional selection at the CHIT1 locus, by comparing worldwide allele frequency variation at the CHIT1 locus to that observed at other loci across the genome.