Gene flow networks among American Aedes aegypti populations

Abstract

The mosquito Aedes aegypti, the dengue virus vector, has spread throughout the tropics in historical times. While this suggests man-mediated dispersal, estimating contemporary connectivity among populations has remained elusive. Here, we use a large mtDNA dataset and a Bayesian coalescent framework to test a set of hypotheses about gene flow among American Ae. aegypti populations. We assessed gene flow patterns at the continental and subregional (Amazon basin) scales. For the Americas, our data favor a stepping-stone model in which gene flow is higher among adjacent populations but in which, at the same time, North American and southeastern Brazilian populations are directly connected, likely via sea trade. Within Amazonia, the model with highest support suggests extensive gene flow among major cities; Manaus, located at the center of the subregional transport network, emerges as a potentially important connecting hub. Our results suggest substantial connectivity across Ae. aegypti populations in the Americas. As long-distance active dispersal has not been observed in this species, our data support man-mediated dispersal as a major determinant of the genetic structure of American Ae. aegypti populations. The inferred topology of interpopulation connectivity can inform network models of Ae. aegypti and dengue spread.

Phylogeography of Aedes aegypti (Yellow Fever Mosquito) in South Florida: mtDNA Evidence for Human-Aided Dispersal

“…aegypti in the Americas using a Bayesian coalescent framework-based gene flow network model analysis. 15 Significant long-distance and human-aided dispersal in Florida may have implications for vector control efforts directed at this species. Such intercity dispersal is likely to interfere with local vector eradication attempts by contributing to recolonization if local eradication is achieved.…”

“…aegypti studied in several other geographic areas. 11,15,[24][25][26][27][28][29][30]54 Discovery of two ND4 mtDNA clusters of Ae. aegypti in Northeastern Mexico provided the first evidence of introductions of two independent mitochondrial lineages or a newly introgressed matriline.…”

“…aegypti in Florida is likely to be distinct from the structure in Asia and Latin America because of differential dispersal potential associated with greater urban sprawl and the lack of opportunities to breed indoors in Florida, 12,14 the larger-scale population genetic structure is expected to be similar to the structure observed elsewhere, showing panmixia because of the wide dispersal capability of the species. 15 Ae. aegypti population history in Florida is complex as a result of founder effects, 16 adaptation, 17 multiple introductions, dispersal, bottlenecks, and expansions.…”

How much is known about the genetic diversity of the Asian tiger mosquito? A systematic review

“…Those results were lower than in other studies on the mtDNA ND4 gene of A. aegypti, a genetic marker widely used in genetic diversity studies in A. aegypti. 47,[77][78] . For instance, in 36 locations in the Americas, Asia and Africa (Hd = 0.80) (79) and five states in Brazil (Hd = 0.80) 80 showed higher genetic diversity than the observed in A. albopictus populations.…”

“…The mtDNA is used for marker analyses largely because of their maternal inheritance, haploid status, and high rate of evolution 47 . The mtDNA is a type of marker used for the recognition of cryptic species, phylogenetic studies and/or genetic structure of populations [48][49][50] .…”