Search

Objective Aedes albopictus is the main indigenous vector of dengue fever in China. Understanding the spatial genetic structure of Aedes albopictus populations, migration, and gene flow is crucial for the effective prevention and control of vector-borne diseases. Methods From June to September 2023, mosquitoes were collected and morphologically identified from eight different geographic locations across tropical, subtropical, and temperate zones of China. Genomic DNA was extracted from individual female mosquitoes, and the mitochondrial cytochrome C oxidase I gene was amplified and sequenced. Population genetic diversity and associated population characteristics were assessed using software such as BioEdit, DnaSP version 6, Arlequin 3.5, and Mega 11. Results A total of 233 samples from eight Aedes albopictus populations across the three climatic zones were successfully sequenced, yielding a gene fragment sequence of 632 bp with 19 variable sites and no insertion or deletion mutations. A total of 21 haplotypes were detected, with H4 being the dominant shared haplotype among the three climate types. Haplotype diversity (Hd) ranged from 0.191 (Beijing population) to 0.887 (Xishuangbanna population), and nucleotide diversity (Pi) ranged from 0.000 51 (Beijing population) to 0.002 98 (Xishuangbanna population), suggesting high haplotype diversity and low nucleotide diversity in Aedes albopictus. The genetic differentiation indices ranged from 0.026 to 0.641, with higher genetic differentiation between temperate and tropical/subtropical regions. The analysis of molecular variation supported that genetic differentiation mainly came from within populations (60.45%). Conclusions The ecological and climatic environment in the tropics results in higher genetic diversity of Aedes albopictus. Human activities have exacerbated the risk of dengue transmission across different climatic zones. [ABSTRACT FROM AUTHOR]

Objective To explore the genetic diversity of Aedes albopictus populations in plain, hilly, and mountainous areas of Hainan Province, and to analyze the genetic structure of Aedes albopictus populations in different terrain regions of Hainan Province. Methods Aedes albopictus were collected from the plain areas of Sanya and Haikou City, the hills of Danzhou and Tunchang City, and the mountainous areas of Baisha City in Hainan Province. DNA was extracted from a single mosquito and stored in a -80 °C refrigerator for use. Mitochondrial cytochrome C oxidase subunit I (mtDNA-CO I) was amplified by PCR and sequenced. The results were compared on the National Center for Biotechnology Information (NCBI) website, sequence peaks were observed using BioEdit 7.0, genetic diversity parameters were calculated using DnaSP v6, haplotype networks were constructed using PopART 1.7, and analysis of molecular variance (AMOVA) values were calculated using Arlequin to analyze differences between populations. Results A total of 414 mtDNA-CO I sequences were obtained from Aedes albopictus populations in 5 regions, with lengths of 663 bp. All sequences had five mutation sites, with a G+C content of 32.86% and an A+T content of 67.14%, consistent with mitochondrial DNA characteristics. Compared with other populations, the nucleotide diversity of the Danzhou and Tunchang populations in the plain and hilly areas was higher. The average nucleotide differences were higher in the Sanya, Tunchang, and Danzhou populations. Haploid analysis revealed 6 haplotypes, with H02 being the dominant haplotype. The Sanya and Tunchang populations had the highest number of haplotypes, while the Haikou and Sanya populations had exclusive haplotypes. Only the plains populations had unique haplotypes, while the hill and mountainous populations had relatively fewer haplotypes. The neutral results and mismatch distribution map indicated that the population of Aedes albopictus has recently expanded in all regions. The AMOVA value showed that the intra-population differences were greater than the inter-population differences. Conclusions The mtDNA-CO I gene can serve as a molecular marker for studying the genetic diversity of Aedes albopictus populations. The Sanya population in the plain region shows higher genetic diversity, and the two populations in the hilly region also have higher genetic diversity. However, the number of haplotypes is only higher in the Sanya population in the plains and the Danzhou population in the hills. [ABSTRACT FROM AUTHOR]