Visualisation of genetic differentiation between H. contortus parental and backcross strains.

Pairwise F_ST estimates and principal component analysis of parental and 4^th generation backcross isolates pre and post ivermectin treatment (0.1 mg/kg ivermectin) using multi-locus genotype data. Figure 3A, B and C shows the data for the MHco3/4 cross and Figure 3D, E and F for the MHco3/10 cross. Both F_ST and PCA analysis was performed with 9 loci and also with 8 loci (when Hcms8a20 was excluded from this latter analysis, since it shows evidence of genetic linkage to the ivermectin resistance phenotype). Figure A and D show pairwise F_ST estimates: values in the tables below the diagonal are for analysis of all 9 loci and above the diagonal for the 8 loci (excluding Hcms8a20). Genetic differentiation between isolates at significance level, p<0.01 (highlighted in bold and italics). Asterisk indicates level of genetic differentiation is marginal (significance at p<0.05). PCA analysis for all 8 loci are shown in panels B and E and for the 9 loci (including 8a20) in panels C and F. Each data point represents a single worm based on a multi-locus genotype of 9 or 8 markers.