Genetic diversity analysis of benzimidazole resistance-associated genes in Haemonchus contortus from four regions in southern Xinjiang.

To assess the genetic diversity of the I β-tubulin haplotype gene associated with benzimidazoles (BZs) resistance in Haemonchus contortus populations across southern Xinjiang, the sampled populations from four distinct areas to detect the BZs resistance-related I-β tubulin gene and analyse its genetic sequences and structure. The results revealed substantial haplotype diversity and nucleotide polymorphisms across the four populations, with nucleotide diversity (Pi) ranging from 0.03471 to 0.10390 and haplotype diversity (Hd) from 0.945 to 1.000. A low genetic differentiation index (Fst) among populations in the four regions ranging from 0.03354 to 0.12056 suggests weak genetic structure differentiation and frequent gene flow between populations. AMOVA indicated that 91 % of genetic variation was due to within-population differences, suggesting minimal impact of geographical location on H. contortus population structure in southern Xinjiang. Phylogenetic and network analyses showed that 36 H. contortus haplotypes from diverse geographic sources clustered into a single branch with interwoven patterns. Notably, drug resistance mutations showed two origins at E198A, while multiple origins likely exist for the F200Y mutation. This study provides the first genetic diversity analysis of benzimidazole resistance-related genes in H. contortus populations in southern Xinjiang, offering preliminary insights into the spread of resistance and supporting disease control efforts.