Genetic Diversity among Four Populations of Aedes aegypti (Diptera: Culicidae) from Honduras as Revealed by Mitochondrial DNA Cytochrome Oxidase I

Abstract

Aedes aegypti is a hematophagous and highly anthropophilic mosquito with a wide distribution, particularly in tropical and subtropical regions of the world. Ae. aegypti is the main vector of several febrile diseases called arboviruses (dengue, yellow fever, chikungunya, and zika viruses), which represent an important public health problem. Populations of this mosquito were nearly eliminated from the Americas in the mid-20th century; however, after the abandonment of control measures, mosquito populations have been recovering territory, have expanded by anthropogenic mechanisms, and have been joined by new populations reintroduced from other continents. The objective of this pilot study was to determine the genetic variability of Aedes aegypti collected in four cities located along the so-called logistics corridor of Honduras, which connects the Caribbean Sea to the Pacific Ocean. We studied the sequences of two molecular markers: the cytochrome c oxidase 1 (COI mtDNA) gene and the internal transcribed spacer 2 (ITS2 rDNA) of 40 mosquitoes. Phylogenetic analyzes show two separate clades with a low number of nucleotide differences per site, three haplotypes, and low haplotype diversity. These results suggest a low genetic diversity in the populations of Ae. aegypti in Honduras in relation to that reported in other countries of the Central American isthmus.

Keywords: Aedes aegypti; COI; Honduras; ITS2 rDNA; genetic diversity.

Figure 1

Phylogenetic cladogram of partial sequences of the Aedes aegypti (a) COI gene, and (b) ITS2 ribosomal region, constructed using the Neighbor-Joining method with a bootstrap of 500 replicates. Each color represents a city where the mosquitoes were collected.

Figure 2

Cladogram (circular tree layout) of partial sequences of the COI gene of Aedes aegypti collected in 48 countries. The Neighbor-Joining method was used with a bootstrap of 500 replicates. Each color represents a world region where the mosquitoes were collected. The black arrows indicate the sequences obtained in this study, and the light blue arrows indicate the sequences reported in El Salvador by Joyce et al., 2018 [20].

Figure 3

(a) Map of Honduras showing three mitochondrial haplotypes (H1–H3) of Ae. qegypti by city. The size of the chart is proportional to the number of individuals per haplotype; (b) haplotype network based on 35 mitochondrial DNA COI sequences of Ae. qegypti collected in four cities of Honduras. Perpendicular bars indicate the number of nucleotide polymorphisms between haplotypes.

Figure 4

Amino acid alignment of a partial sequence of Cytochrome oxidase 1 protein from Aedes aegypti (top) and Ae. albopictus (bottom). The red arrow shows the only position where there is a substitution (serine for alanine).

Figure 5

(a) Map of Honduras showing the location of four cities where the mosquitoes were collected. The orange line represents the road CA-5 connecting the cities. The map shows the country’s ecoregions according to the Köppen–Geiger climate classification. Adapted from [49]; (b) satellite images of the four cities indicating the geographic point (orange dot) where the eggs of the mosquitoes were collected. Adapted from Google.com/maps (accessed on 4 May 2022).