Abstract：
Ticks are hematophagous ectoparasites associated with a wide range of vertebrate hosts. Within this group, the Ixodidae family stands out, in which the Ixodes genus contains at least 245 species worldwide, from which 55 species are present in the Neotropical region. Ixodes affinis, a tick described in 1899, has a wide distribution from the Southern Cone of America to the United States. However, since its description, morphological variability has been reported among its populations. Furthermore, attempts have been made to clarify its status as a species complex using mitochondrial markers, but mainly in restricted populations of South and Central America. Thus, information related to populations of the transition region between the Neotropical and Nearctic zones is lacking. For these reasons, the objectives of the study were to evaluate the genetic diversity and structure of I. affinis across the Americas and to compile all the published records of I. affinis in America, to elucidate the host-parasite relationships and to identify their geographical distribution. For this, a phylogeny, and AMOVA analyses were performed to assess the genetic structure of samples obtained by field work in South Carolina, USA and Yucatán, Mexico. A total of 86 sequences were retrieved from a fragment of the 16S region. Phylogeny and genetic structure analysis showed four groups that were geographically and genetically related with high branch support and Fst values, all of them statistically significant. The results obtained support the hypothesis that I. affinis it corresponds to a complex of four species, which must be validated through future morphological comparisons.
摘要：
蜱是与多种脊椎动物宿主相关的嗜血体外寄生虫。在这个群体中,Ixodidae家族脱颖而出，其中Ixodes属在世界范围内至少包含245种，其中55种存在于新热带地区。Ixodesaffinis，1899年描述的一种蜱，从美国南锥体到美国都有广泛的分布。然而,因为它的描述，据报道，其种群之间存在形态变异性。此外，已经尝试使用线粒体标记来阐明其作为物种复合体的状态，但主要在南美洲和中美洲的限制人口中。因此，缺乏与新热带和近地带之间过渡区域种群有关的信息。由于这些原因,这项研究的目的是评估整个美洲I.affinis的遗传多样性和结构，并汇编所有已发表的I.affinis在美国的记录，阐明宿主与寄生虫的关系并确定其地理分布。为此，一个系统发育,和AMOVA分析进行了评估遗传结构的样品通过实地工作在南卡罗来纳州，美国和尤卡坦,墨西哥。从16S区的片段中检索到总共86个序列。系统发育和遗传结构分析表明，在地理和遗传上具有较高的分支支持和Fst值，所有这些都具有统计学意义。获得的结果支持以下假设：I.affinis它对应于四个物种的复合物，这必须通过未来的形态学比较来验证。
