Current Research Areas

Juvenile white-tailed deer in New Jersey

Culex pipiens f. molestus

An Alaskan bloodfeeder!

Area 1: Characterization of enzootic cycles and population divergence in the tick-vectored bacterium, Anaplasma phagocytophilum

Anaplasma phagocytophilum is a tick-transmitted, obligately intracellular pathogen of humans, pets and livestock. Strains of A. phagocytophilum display varying degrees of host specialization in Europe, but much less is known about host-affiliations and transmission cycles in North America. The Aardema lab is working to better characterize the distinct cycles of A. phagocytophilum transmission both in the United States and Europe, as well as exploring relationships between these two bacterial populations. We are also interested in host adaptation and divergent selection in this bacterium. These inquires may ultimately lead to improved prevention of human, pet and livestock infections.

Select Publications:
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Aardema ML (2023) Genomic analyses indicate the North American Ap-ha variant of the tick-vectored bacterium Anaplasma phagocytophilum was introduced from Europe. Parasites & Vectors. 16:301.

Kruppenbacher A-S, Müller E, Aardema ML, Schäfer I, von Loewenich FD (2023) Granulocytic anaplasmosis in cats from central Europe and molecular characterization of feline Anaplasma phagocytophilum strains by ankA gene, groEL gene and multilocus sequence typing. Parasites & Vectors. 16:348.

Aardema ML, Archer QE, Bates N, von Loewenich FD (2022) Demographic expansions and the emergence of host specialization in genetically distinct ecotypes of the tick-transmitted bacterium Anaplasma phagocytophilum. Applied and Environmental Microbiology. 88:e0061722.

Langenwalder D, Schmidt S, Gilli U, Pantchev N, Ganter M, Aardema ML, Silaghi C, von Loewenich FD (2019) Genetic characterization of Anaplasma phagocytophilum strains from goats and water buffalo by 16S rRNA gene, ankA gene and multilocus sequence typing. Ticks and Tick-Borne Diseases. 10:101267.

Aardema ML, von Loewenich FD (2015) Varying influences of selection and demography in host adapted populations of the tick-transmitted bacterium, Anaplasma phagocytophilum. BMC Evolutionary Biology 15:58.

​Huhn C, Winter C, Wolfsperger T, Wüppenhorst N, Strašek Smrdel K, Skuballa J, Pfäffle M, Petney T, Silaghi C, Dyachenko V, Straubinger RK, Schaarschmidt-Kiener D, Ganter M, Aardema ML, von Loewenich FD (2014) Analysis of the population structure of Anaplasma phagocytophilum using multilocus sequence typing. PLoS One 9:e93725.

Area 2: Admixture, population structure and evolutionary patterns of taxonomic divergence in the Culex pipiens complex of mosquitos

Within the Culex pipiens mosquito complex there are six contemporarily recognized taxa. Despite morphological and genetic similarities, these mosquitos differ in important physiological, behavioral, and ecological aspects that affect their ability to vector human pathogens. This creates the need for a clear understanding of the relationships between these mosquitos, as this will allow us to better evaluate potential disease transmission cycles and establish control strategies. Hybridization ('admixture') between these taxa further complicates our understanding of these disease vectors. The Aardema lab combines genomic and transcriptomic data with experiments on lab colonies of Culex mosquitoes to answer evolutionary and ecological questions about these insects.​

Select Publications:

​Aardema ML, Campana MG, Wagner NE, Ferreira FC, Fonseca DM (2022) A gene-based capture assay for surveying patterns of genetic diversity and insecticide resistance in a worldwide group of invasive mosquitoes. PLoS Neglected Tropical Diseases. 16:e0010689.

Aardema ML, Olatunji SK*, Fonseca DM (2022) The enigmatic Culex pipiens species complex: phylogenetic challenges and opportunities from a notoriously tricky mosquito group. Annals of the American Entomological Society. 115:95-104.

Epstein NR, Saez K, Polat A, Davis SR, Aardema ML (2021) The urban-adapted underground mosquito, Culex pipiens form molestus, maintains exogenously influenceable circadian rhythms. Journal of Experimental Biology. 224:jeb242231.

Aardema ML, vonHoldt BM, Fritz ML, Davis SR (2020) Global evaluation of taxonomic relationships and genetic exchange within the Culex pipiens complex of mosquitoes. Parasites & Vectors. 13:8.

Area 3: Convergent and Parallel Genomic Evolution in Arthropods

The incredible biological diversity of arthropods, especially insects, means that similar evolutionary solutions to ecological problems have arisen independently in numerous, phylogenetically distinct lineages. Such parallel and convergent evolution provides opportunities for understanding the ways in which underlying genomic architecture can facilitate or restrict the emergence of novel adaptations. The Aardema lab has lead or contributed to investigations of convergent evolution in multiple systems, chiefly milkweed-feeding insects, fireflies, and  rove beetles.

​Currently, the Aardema lab is leading investigations of genetic convergence in blood-feeding arthropods. Blood represents a challenging and potentially toxic food source for most animal species. Nonetheless, numerous arthropods such as ticks, mosquitos, bedbugs and fleas have evolved the ability to utilize and thrive on vertebrate blood. Using whole-genome data from a large number of phylogenetically distinct species, the Aardema lab is examining three areas of potential evolutionary convergence among blood-feeding arthropods: tyrosine detoxification, heme detoxification and water balance.

Select Publications:

Kitchen S, Naragon T, Brückner A, Ladinsky M, Quinodoz S, Badroos J, Viliunas J, Wagner J, Miller D, Yousefelahiyeh M, Antoshechkin I; Eldredge KT, Pirro S, Guttman M, Davis S, Aardema ML, Parker J (2024) The genomic and cellular basis of biosynthetic innovation in rove beetles. Cell. DOI: https://doi.org/10.1016/j.cell.2024.05.012.
 
Yang L, Borne F, Betz A, Aardema ML, Zhen Y, Peng J, Visconti R, Wu M, Roland BP, Talsma AD, Palladino MJ, Petschenka G, Andolfatto P (2023) Predatory fireflies and their toxic firefly prey have evolved distinct toxin resistance strategies. Current Biology. 33:5160-5168.

Aardema ML, Andolfatto P (2016) Phylogenetic incongruence and the evolutionary origins of cardenolide-resistant forms of Na+,K+-ATPase in Danaus butterflies. Evolution 70:1913-1921.

Zhen Y, Aardema ML, Medina EM, Schumer M, Andolfatto P (2012) Parallel molecular evolution in an herbivore community. Science 337:1634-1637.
  
Aardema ML, Zhen Y, Andolfatto P (2012) The evolution of cardenolide-resistant forms of Na+,K+- ATPase in Danainae butterflies. Molecular Ecology 21:340-349.​