Faculty of Science, Department of Biology, Division of Ecology, Hacettepe University, 06800, Beytepe, Ankara, Türkiye.
Faculty of Science, Department of Molecular Biology and Genetics, Koc University, 34450, Ýstanbul, Türkiye.
Parasit Vectors. 2024 Nov 19;17(1):477. doi: 10.1186/s13071-024-06530-z.
Ticks are crucial vectors of a wide range of pathogens, posing significant threats to human and animal health globally. Understanding the genetic basis of tick biology and host-parasite interactions is essential for developing effective control programs. This study investigates the fine-scale genetic structure of Hyalomma marginatum Koch, 1844, the primary vector of Crimean-Congo hemorrhagic fever (CCHF) in Türkiye. Despite its significant public health importance, information regarding its population structure and genetic diversity is quite limited.
We used restriction site-associated DNA sequencing (RAD-Seq) to obtain genome-wide sequence data from 10 tick populations in Türkiye, collected from regions with low, moderate, and high incidence rates of CCHF. Based on these data, we determined population structure and diversity of populations using principal component analysis (PCA) and admixture analysis. Furthermore, we calculated pairwise F and utilized discriminant analysis of principal components (DAPC) to understand genetic differentiation between populations.
PCA and admixture analysis indicated minimal genetic structure between populations, but we detected notable genetic differentiation and high genetic diversity from regions with high CCHF rates. Furthermore, our DAPC identified 31 significant single-nucleotide polymorphisms (SNPs) associated with regions with high CCHF incidence, with 25 SNPs located near genes involved in critical biological functions such as nucleic acid binding, transmembrane transport, and proteolysis. These findings suggest that genetic variations in these regions may confer adaptive advantages in environments with high pathogen loads.
This study provides the first comprehensive analysis of H. marginatum genetic diversity in Türkiye, revealing significant differentiation in populations from CCHF-endemic regions. These results underscore the importance of considering fine-scale genetic diversity to fully understand the drivers of genetic variation in ticks and their implications for vectorial capacity.
蜱是多种病原体的重要载体，对全球人类和动物健康构成重大威胁。了解蜱的生物学和宿主-寄生虫相互作用的遗传基础对于制定有效的控制计划至关重要。本研究调查了土耳其主要的克里米亚-刚果出血热（CCHF）媒介钝缘蜱（Hyalomma marginatum Koch，1844）的精细遗传结构。尽管它具有重要的公共卫生意义，但关于其种群结构和遗传多样性的信息相当有限。
我们使用限制酶相关 DNA 测序（RAD-Seq）从土耳其的 10 个蜱种群中获得了全基因组序列数据，这些种群来自 CCHF 发病率低、中、高的地区。基于这些数据，我们使用主成分分析（PCA）和混合分析来确定种群结构和多样性。此外，我们计算了成对 F 值，并利用主成分判别分析（DAPC）来理解种群之间的遗传分化。
PCA 和混合分析表明种群之间的遗传结构很小，但我们发现来自 CCHF 发病率高的地区存在显著的遗传分化和高遗传多样性。此外，我们的 DAPC 确定了 31 个与 CCHF 发病率高的地区相关的显著单核苷酸多态性（SNP），其中 25 个 SNP 位于与关键生物学功能（如核酸结合、跨膜运输和蛋白水解）相关的基因附近。这些发现表明，这些区域的遗传变异可能赋予了在高病原体负荷环境中的适应性优势。
本研究首次对土耳其的钝缘蜱遗传多样性进行了全面分析，揭示了来自 CCHF 流行地区的种群存在显著分化。这些结果强调了考虑精细遗传多样性的重要性，以充分了解蜱类遗传变异的驱动因素及其对媒介能力的影响。
