Fig 1.
Prevalence of parasitic nematode species identified on the seven study farms and parasite population structure.
(A) The relative frequencies of the eight major ovine gastro-intestinal nematode species based on species-specific PCR assays on 90 individual L1 larvae on the seven study farms. (B) Pairwise FST values based on genotyping with ten microsatellite loci for H. contortus and T. circumcincta respectively. FST values estimated before correction for null alleles below the diagonal and after correction above. Values underlined and in bold show significant differences based on bootstrapping (10, 000 replicates) using the software program FreeNA. (C) SplitsTrees4 Networks based on populations of thirty worms on each farm genotyped using ten microsatellite markers for each species.
Table 1.
Allelic diversity of microsatelllite loci and β-tubulin from H. contortus and T. circumcincta from each of the seven study farms and neutrality test statistics.
Fig 2.
The relative proportions of isotype-1 β-tubulin alleles encoding resistance-conferring polymorphisms at F167Y, E198L or F200Y.
Populations for (A) H. contortus and (B) T. circumcincta, consisting of 30 or 32 individual worms, were pyrosequence genotyped at the three benzimidzole resistance associated SNPs in separate assays to determine the proportion of each SNP in each population.
Fig 3.
Relative frequency of individual resistant haplotypes in seven UK sheep parasite populations.
A total number of five resistant haplotypes for (A) H. contortus and twenty eight resistant haplotypes for (B) T. circumcincta were identified. Susceptible haplotypes are not included this figure but are show in S3 Fig.
Fig 4.
Network analysis of sequences of isotype-1 β-tubulin sequences.
Split networks were generated with the neighbour-net method of SplitsTrees4 from (A) H. contortus sequences and (B) T. circumcincta sequences. The circles in Split networks represent the different haplotype and the size of the circles is proportional to the frequency in the population. The colours define the resistant haplotypes across positions P167, P198 and P200 (P167F:P198E:P200F, Susceptible = blue; P167F:P198E:P200Y, Resistant at P200 = Red; P167Y:P198E:P200F, Resistant at P167 = green; P167F:P198L:P200F, Resistant at P198 = orange).