Data from: Contrasting definitive hosts as determinants of the genetic structure in a parasite with complex life cycle along the Southeastern Pacific

The spatial genetic structure (and gene flow) of parasites with complex life cycles, such as digeneans, has been attributed mainly to the dispersion ability of the most mobile host, which most often corresponds to the definitive host (DH). In this study, we compared the genetic structure and diversity of adult Neolebouria georgenascimentoi in two fish species (DHs) that are extensively distributed along the Southeastern Pacific (SEP). The analysis was based on the cytochrome oxidase subunit I gene sequences of parasites collected between 23°S and 45°S. In total, 202 sequences of N. georgenascimentoi in Pinguipes chilensis isolated from 9 sites and 136 sequences of Prolatilus jugularis from 5 sites were analyzed. Our results showed that N. georgenascimentoi is a species complex that includes three different parasite species; however, in this study, only lineage 1 and 2 found in P. chilensis and P. jugularis, respectively, were studied because they are widely distributed along the coastline. Lineage 1 parasites had two common haplotypes with wide distribution and unique haplotypes in northern sites. Lineage 2 had only one common haplotype with wide distribution and a large number of unique haplotypes with greater genetic diversity. Both groups have experienced recent population expansion. Only lineage 1 exhibited a genetic structure that was mainly associated with a biogeographic break at approximately 30°S along the SEP. Our finding suggests that host access to different prey (=intermediate hosts) could affect the genetic structure of the parasite complex discovered here. Consequently, the difference between these patterns suggests that factors other than DH dispersal (e.g., wider range of intermediate hosts) are involved in the genetic structure of autogenic parasites.

具有复杂生活史的寄生虫（如复殖吸虫（digeneans））的空间遗传结构与基因流，主要归因于流动性最强宿主的扩散能力，这类宿主通常为终末宿主（definitive host, DH）。本研究针对东南太平洋（Southeastern Pacific, SEP）沿岸广泛分布的两种鱼类终末宿主，比较了其体内寄生的成虫Neolebouria georgenascimentoi的遗传结构与多样性。分析基于23°S至45°S区间内采集的寄生虫的细胞色素氧化酶亚基I（cytochrome oxidase subunit I）基因序列。本研究共分析了9个采样点的智利平鳍鱶（Pinguipes chilensis）体内的202条Neolebouria georgenascimentoi序列，以及5个采样点的颈斜口鳚（Prolatilus jugularis）体内的136条序列。研究结果显示，Neolebouria georgenascimentoi是一个包含3个独立寄生虫物种的复合群；但本研究仅针对分别寄生于智利平鳍鱶与颈斜口鳚的谱系1和谱系2展开分析——这两类谱系均沿东南太平洋沿岸广泛分布。谱系1的寄生虫存在两种广布的常见单倍型（haplotype），且在北部采样点存在特有单倍型；谱系2仅有一种广布的常见单倍型，且存在大量特有单倍型，遗传多样性更高。两类谱系均经历过近期的种群扩张事件。仅谱系1呈现出与东南太平洋沿岸约30°S处的生物地理断点（biogeographic break）相关的遗传结构。本研究结果提示，宿主对不同猎物（即中间宿主（intermediate hosts））的获取途径，可能会影响本次发现的寄生虫复合群的遗传结构。因此，这些模式间的差异表明，除终末宿主扩散外的其他因素（如中间宿主范围更广），参与调控了自体寄生寄生虫的遗传结构。