Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
Biomedical Science Program, Graduate School, Khon Kaen University, Khon Kaen 40002, Thailand.
Infect Genet Evol. 2021 Jul;91:104825. doi: 10.1016/j.meegid.2021.104825. Epub 2021 Mar 26.
Pediculus humanus (human louse) is a hematophagous insect that feeds on human blood. It is distributed worldwide. Understanding phylogeography and population-genetic structure of the human louse will illuminate the evolution of this insect and the dynamics of how resistance alleles might spread in the landscape. In this work, we used mitochondrial (cox1 and cytb genes) sequences of the human louse to investigate genetic diversity, population-genetic structure and demographic history of the louse in Thailand. Human lice in Thailand belonged to mitochondrial clades A and C. Most genetic variation was attributed to intra-region 65.71% within provinces for clade A and 68.92% for clade C, while inter-region level was 34.40% among provinces within regions for clade A and 20.09% for clade C. Neutrality and other indices suggested that louse populations from clades A and C in Thailand have experienced a population expansion. But head lice from Khon Kaen Province in clade C demonstrated a significant recent population bottleneck or natural selective pressure with constant population size. Head lice in Thailand showed varying degrees of low to high genetic differentiation at the level of province with many populations being genetically distinct from each other among regions and within the same region. Knowledge of the clades present in Thailand and that gene flow occurs between regions will assist in developing appropriate strategies for management of head lice at the local level in the country.
人体虱（人虱）是一种吸血昆虫，以人类血液为食。它分布于世界各地。了解人体虱的系统地理学和种群遗传结构将阐明这种昆虫的进化以及抗性等位基因在景观中传播的动态。在这项工作中，我们使用人体虱的线粒体（cox1 和 cytb 基因）序列来研究泰国人体虱的遗传多样性、种群遗传结构和种群历史。泰国人体虱属于线粒体支系 A 和 C。大多数遗传变异归因于省内的区域内变异（65.71% 为支系 A，68.92% 为支系 C），而区域间水平为省内的区域间变异（支系 A 为 34.40%，支系 C 为 20.09%）。中性和其他指标表明，来自泰国支系 A 和 C 的人体虱种群经历了种群扩张。但支系 C 的孔敬省头虱显示出最近种群瓶颈或恒定种群大小的自然选择压力的显著影响。泰国头虱在省级水平上表现出不同程度的低到高遗传分化，许多种群在区域之间和同一区域内彼此之间存在明显的遗传差异。了解泰国存在的支系以及区域之间发生基因流的情况，将有助于制定在该国地方一级管理头虱的适当策略。
