Principal Component
Analysis
The principal component analysis showed similar population structure as
the fastSTRUCTURE analysis. PC1 and PC2 explain 29.68% and 6.41% of
variation, respectively, and separated the sub-Saharan African samples
from the rest very clearly (Figure 5). In addition, we observed the same
clustering patterns of lice in the fastSTRUCTURE results, including the
same outliers (Figure 4). For example, in the PCA, Asia is subdivided
into South Asia and Southeast Asia (See table 2 for details on countries
that belong to each region), where the Southeast Asian cluster includes
individuals from Oceania. Similarly, the main outliers detected in the
fastSTRUCTURE analysis were Hungary, Mongolia and Egypt, clustering
together with South Asian individuals, and all of the Algerian lice
clustering with Europeans. These were also observed in the PCA clusters.