Genomic profiling of climate adaptation in Aedes aegypti along an altitudinal gradient in Nepal indicates nongradual expansion of the disease vector

Abstract

Driven by globalization, urbanization and climate change, the distribution range of invasive vector species has expanded to previously colder ecoregions. To reduce healththreatening impacts on humans, insect vectors are extensively studied. Population genomics can reveal the genomic basis of adaptation and help to identify emerging trends of vector expansion. By applying whole genome analyses and genotypeenvironment associations to populations of the main dengue vector Aedes aegypti, sampled along an altitudinal gradient in Nepal (200-1300 m), we identify putatively adaptive traits and describe the species' genomic footprint of climate adaptation to colder ecoregions. We found two differentiated clusters with significantly different allele frequencies in genes associated to climate adaptation between the highland population (1300 m) and all other lowland populations (≤800 m). We revealed nonsynonymous mutations in 13 of the candidate genes associated to either altitude, precipitation or cold tolerance and identified an isolation-by-environment differentiation pattern. Other than the expected gradual differentiation along the altitudinal gradient, our results reveal a distinct genomic differentiation of the highland population. Local high-altitude adaptation could be one explanation of the population's phenotypic cold tolerance. Carrying alleles relevant for survival under colder climate increases the likelihood of this highland population to a worldwide expansion into other colder ecoregions. K E Y W O R D S climate change genomics, latent factor mixed model, range expansion, whole genome pooled sequencing, yellow fever mosquito | 351 KRAMER et al.

Susceptibility to cold suggests low risk of establishment of a tropical parasitoid attacking the corn pest Sesamia nonagrioides

“…Genetic variation of cold resistance traits was found within a beetle species, which establish populations that successfully survive cold climates during winter months (Zhao et al, 2018). Significant differences in allele frequencies of genes associated to climate adaptation were also found between populations of the mosquito Aedes aegypti (Kramer et al, 2023), showing adaptation of a tropical species to cooler climates.…”

“…At the cellular level, cold-susceptible insects die from exposure to cold temperatures above zero due to loss of ion and water balance linked to alterations in the function, composition and structure of their cytoplasmic membrane, especially severe at the gut and Malpighian tubules level (Overgaard and MacMillan, 2017). At the molecular level, transcriptomic analyses run in different insect orders have pointed out numerous genes and proteins involved in responses to cold temperatures (Des Marteaux et al, 2017;Dunning et al, 2014;Kramer et al, 2023;Toxopeus et al, 2019) and their functions are being progressively identified (De Jong and Saastamoinen, 2018;Guz et al, 2014;Poikela et al, 2021;Zhang et al, 2020). For instance, polymorphism is an amino acid in the gene flightin, known to have an important function in insect flight and locomotion, was associated with chill coma recovery in a Nymphalid butterfly (De Jong and Saastamoinen, 2018).…”

Distribuição Espacial E Temporal De Internações Por Dengue No Brasil De 2008 a 2020

“…Apesar de ocorrer principalmente nas regiões tropicais e subtropicais a infecção por dengue afeta mais de 100 países distribuídos também nas demais regiões climáticas (Brady et al, 2012). Assim, outros fatores devem ser levados em consideração, tais como o aquecimento global, o aumento populacional e a frequência de viagens aéreas, crescimento urbano descontrolado e sem planejamento e ineficiência no controle do vetor assim como, sua adaptação climática (Hasan et al, 2016); já existindo registros de dengue em regiões temperadas, como no Nepal (Kramer et al, 2023) e países da Europa (Re et al, 2020).…”