2.5 Detection of Non-African Admixture

To investigate whether the presence of the MtnA 3’ UTR deletion in the Zambian population was better explained by ancestral polymorphism or more recent non-African admixture, we constructed a neighbor-joining tree for a 15 kb region surrounding MtnA using 20 Zambian sequences (five of which contained the deletion) and 20 sequences from Lyon, France [32,33]. Only aligned nucleotides were considered for tree construction (i.e., indels were excluded) using MEGA 7.0.26 [39]. Node support was assessed by doing 1000 bootstrap iterations [40]. The tree was rooted using the reference sequences of D. sechellia and D. simulans as outgroups [41] and edited using the R package APE 5.2 [42].