Fig. 1
From: Biases of STRUCTURE software when exploring introduction routes of invasive species
Schematic representations of the main STRUCTURE clustering patterns that can be obtained at K = 3 and K = 2 according to different invasion scenarios (either independent or serial) involving one native and two invasive populations. Other patterns with admixture are also possible but are not shown here because they are less informative in the context of invasion routes. At K = 3, with 3 samples, the same pattern (i.e., each sample constitutes a cluster) is likely to be found whatever the scenario, and thus no valuable information about the origin of introduced populations can be deduced. On the contrary, patterns obtained at K = 2 can be informative: whereas clustering patterns a and b can be obtained in both independent and serial scenario, pattern c should only be found if introductions are serial. If obtained, this pattern c would lead a STRUCTURE user to eliminate the independent scenario as a likely one
