Pinheiro Iara Carolini, Voges Kamila, Yoshikawa Andre Akira Gonzaga, Cardoso Sabrina Fernandes, Carvalho Antonio Bernardo, Pitaluga André Nóbrega, Rona Luísa Damazio Pitaluga
Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genética, Florianópolis, SC, Brasil.
Secretaria de Estado da Saúde de Santa Catarina, Diretoria de Vigilância Epidemiológica, Florianópolis, SC, Brasil.
Mem Inst Oswaldo Cruz. 2025 Jul 21;120:e240287. doi: 10.1590/0074-02760240287. eCollection 2025.
Malaria, caused by protozoa of the genus Plasmodium and transmitted by Anopheles mosquitoes, remains a significant global health concern. In 2022, approximately 249 million malaria cases were reported worldwide, including 163,000 in Brazil. In the Atlantic Forest, An. bellator and An. cruzii are the primary vectors of malaria transmission.
This study used a cytochrome C oxidase I (COI) gene fragment to investigate the genetic population structure of An. bellator in the Brazilian Atlantic Forest.
Mosquitoes were collected from Itaparica (BA), Camacan (BA), Ilha Grande (RJ), Antonina (PR), Ilha do Mel (PR), and Florianópolis (SC). They were morphologically identified and individually photographed. DNA was extracted, and a COI gene fragment was amplified using polymerase chain reaction (PCR), purified, and sequenced. Additionally, sequences from Trinidad, Colombia, and São Paulo State, obtained from GenBank, were included in the analysis. These sequences were used for molecular identification, genetic variation analysis within and between populations, and phylogenetic assessment.
The analysis revealed that the An. bellator population from Trinidad is genetically distinct from all analysed populations. Furthermore, the Camacan population forms a distinct group separate from the Itaparica population, with both differing from the southern Brazilian populations and that of Colombia. Additionally, the data suggest that the southern Brazilian populations may represent distinct incipient species, particularly the Ilha Grande sample. This divergence is strongly supported by fixed genetic differences, high F ST values, and genealogical analysis.
The findings provide strong evidence of cryptic species within An. bellator, which appears to consist of at least three sibling groups: one from Trinidad and Tobago; An. bellator B, which includes sequences from Camacan; and An. bellator A, which contains sequences from Colombia, Itaparica, Ilha Grande, São Paulo, Florianópolis, Ilha do Mel, and Antonina. Despite its geographical proximity to Camacan (280 km), the Itaparica population clusters with southern populations ~2,000 km away, while remaining genetically distinct from them. Additionally, the study identified higher F ST values between the Ilha Grande population and other southern Brazilian samples, highlighting further genetic divergence.
疟疾由疟原虫属原生动物引起，通过按蚊传播，仍然是全球重大的健康问题。2022年，全球报告了约2.49亿例疟疾病例，其中巴西有16.3万例。在大西洋森林地区，贝氏按蚊和克鲁兹按蚊是疟疾传播的主要媒介。
本研究使用细胞色素C氧化酶I（COI）基因片段来研究巴西大西洋森林地区贝氏按蚊的遗传种群结构。
从伊塔帕里卡（巴伊亚州）、卡马坎（巴伊亚州）、大岛（里约热内卢州）、安东尼亚（巴拉那州）、梅尔岛（巴拉那州）和弗洛里亚诺波利斯（圣卡塔琳娜州）采集蚊子。对它们进行形态学鉴定并逐个拍照。提取DNA，使用聚合酶链反应（PCR）扩增COI基因片段，纯化并测序。此外，从GenBank获取的来自特立尼达、哥伦比亚和圣保罗州的序列也纳入分析。这些序列用于分子鉴定、种群内部和种群之间的遗传变异分析以及系统发育评估。
分析表明，来自特立尼达的贝氏按蚊种群在基因上与所有分析的种群不同。此外，卡马坎种群形成了一个与伊塔帕里卡种群不同的独特群体，两者都与巴西南部种群和哥伦比亚种群不同。此外，数据表明巴西南部种群可能代表不同的初始物种，特别是大岛样本。这种差异得到了固定遗传差异、高F ST值和谱系分析的有力支持。
研究结果为贝氏按蚊中存在隐存种提供了有力证据，贝氏按蚊似乎至少由三个姐妹群体组成：一个来自特立尼达和多巴哥；贝氏按蚊B，包括来自卡马坎的序列；以及贝氏按蚊A，包含来自哥伦比亚、伊塔帕里卡、大岛、圣保罗、弗洛里亚诺波利斯、梅尔岛和安东尼亚的序列。尽管伊塔帕里卡种群与卡马坎地理位置接近（280公里），但它与约2000公里外的南部种群聚类，同时在基因上又与它们不同。此外，研究发现大岛种群与巴西南部其他样本之间的F ST值更高，突出了进一步的遗传差异。
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