CHIT1 duplication distribution in human populations (in blue the 24-bp duplication, in red the Wt). Allele frequencies represented in the map are (from left to right) for the following countries: Burkina Faso (Wt freq.: 98%) (Malaguarnera et al., 2003), South Africa (100%) (Arndt et al., 2013), Spain (Basques) (88%) (Piras et al., 2007a, Piras et al., 2007b), The Netherlands (77%) (Boot et al., 1998), Sicily (73%) (Piras et al., 2007a, Piras et al., 2007b), India (60%) (Choi et al., 2001), Papua New Guinea (88%) (Hise et al., 2003), Chinese Han, Taiwan (42%) (Chien, Chen, & Hwu, 2005), Mexico (76%) (Juárez-Rendón, Lara-Aguilar, & García-Ortiz, 2013), Brazil (74%) (Adelino et al., 2013) and Amerindians of Peru (52%). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)