Spatial and temporal TLR3 variation across islands
No significant deviation from HWE was observed in any of the different island populations, either pre- or post- translocation (Table S4). All populations showed the same overall trend, withTLR3 C alleles decreasing in frequency over time (Fig 4), but the rate of change differed between islands (Table 3, Fig 4). As shown above, TLR3 C allele frequencies on Cousin were significantly lower in 2018 compared to 1993-94 (P<0.001, Table 3, Fig 4). Of the translocated populations, only Denis showed a significant decline in TLR3 Callele frequency between the initial and most recent sample (15 years difference; P = 0.002; Fig 4; Table 3). TLR3 allele frequency temporal differences for Frégate (7 years difference), and between the oldest samples from the source population (Cousin) and the contemporary samples from Aride and Cousine (20 or 28-year difference respectively) were not significant (Fig 4; Table 3).
Focusing on the most recent samples, we found significant TLR3differentiation between Denis and Aride (P = 0.001; Table 3), Denis and Cousine (P = 0.009; Table 3), and Aride and Cousin (P = 0.022; Table 3). Denis had the lowest frequency ofTLR3 C alleles (22%) while Aride had the highest (39%) (see Fig 4). All other pairwise comparisons were not significant (Table 1).