Population Structure
At K=2, fastSTRUCTURE results show a clear separation of lice collected in Africa from the rest of the regions, including a few admixed samples in Asia (Figure 4). As the number of K increases, the genetic clusters start to separate the samples by continents and further subdividing into sub-continents. Out of the 10 K-values tested, the optimum value of K for this dataset was K=5. The five genetic clusters (Figure 4) separate out individuals as follows: Sub-Saharan African (orange cluster), Southeast Asian and Oceanian (dark blue cluster), South Asia (green cluster), Central and South America (maroon cluster), and Europe with the majority of North America (light blue cluster). There are a few exceptions to these general categorizations of individuals. Some that stand out are samples from Hungary, Egypt, Mongolia, Turkey, and Israel. Both fastSTRUCTURE and ADMIXTURE analyses produced identical results. Therefore, we only report fastSTRUCTURE results on the overall genetic population structure.