Browsing by Author "Caccone, Adalgisa"

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    Ancient and modern colonization of North America by hemlock woolly adelgid, Adelges tsugae (Hemiptera: Adelgidae), an invasive insect from East Asia
    Havill, Nathan P.; Shiyake, Shigehiko; Galloway, Ashley Lamb; Foottit, Robert G.; Yu, Guoyue; Paradis, Annie; Elkinton, Joseph S.; Montgomery, Michael E.; Sano, Masakazu; Caccone, Adalgisa (2016-05)
    Hemlock woolly adelgid, Adelges tsugae, is an invasive pest of hemlock trees (Tsuga) in eastern North America. We used 14 microsatellites and mitochondrial COI sequences to assess its worldwide genetic structure and reconstruct its colonization history. The resulting information about its life cycle, biogeography and host specialization could help predict invasion by insect herbivores. We identified eight endemic lineages of hemlock adelgids in central China, western China, Ulleung Island (South Korea), western North America, and two each in Taiwan and Japan, with the Japanese lineages specializing on different Tsuga species. Adelgid life cycles varied at local and continental scales with different sexual, obligately asexual and facultatively asexual lineages. Adelgids in western North America exhibited very high microsatellite heterozygosity, which suggests ancient asexuality. The earliest lineages diverged in Asia during Pleistocene glacial periods, as estimated using approximate Bayesian computation. Colonization of western North America was estimated to have occurred prior to the last glacial period by adelgids directly ancestral to those in southern Japan, perhaps carried by birds. The modern invasion from southern Japan to eastern North America caused an extreme genetic bottleneck with just two closely related clones detected throughout the introduced range. Both colonization events to North America involved host shifts to unrelated hemlock species. These results suggest that genetic diversity, host specialization and host phylogeny are not predictive of adelgid invasion. Monitoring non-native sentinel host trees and focusing on invasion pathways might be more effective methods of preventing invasion than making predictions using species traits or evolutionary history.
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    Improved reference genome of the arboviral vector Aedes albopictus
    Palatini, Umberto; Masri, Reem A.; Cosme, Luciano V.; Koren, Sergey; Thibaud-Nissen, Françoise; Biedler, James K.; Krsticevic, Flavia; Johnston, J. Spencer; Halbach, Rebecca; Crawford, Jacob E.; Antoshechkin, Igor; Failloux, Anna-Bella; Pischedda, Elisa; Marconcini, Michele; Ghurye, Jay; Rhie, Arang; Sharma, Atashi; Karagodin, Dmitriy A.; Jenrette, Jeremy; Gamez, Stephanie; Miesen, Pascal; Masterson, Patrick; Caccone, Adalgisa; Sharakhova, Maria V.; Tu, Zhijian Jake; Papathanos, Philippos A.; Van Rij, Ronald P.; Akbari, Omar S.; Powell, Jeffrey R.; Phillippy, Adam M.; Bonizzoni, Mariangela (2020-08-26)
    Background The Asian tiger mosquito Aedes albopictus is globally expanding and has become the main vector for human arboviruses in Europe. With limited antiviral drugs and vaccines available, vector control is the primary approach to prevent mosquito-borne diseases. A reliable and accurate DNA sequence of the Ae. albopictus genome is essential to develop new approaches that involve genetic manipulation of mosquitoes. Results We use long-read sequencing methods and modern scaffolding techniques (PacBio, 10X, and Hi-C) to produce AalbF2, a dramatically improved assembly of the Ae. albopictus genome. AalbF2 reveals widespread viral insertions, novel microRNAs and piRNA clusters, the sex-determining locus, and new immunity genes, and enables genome-wide studies of geographically diverse Ae. albopictus populations and analyses of the developmental and stage-dependent network of expression data. Additionally, we build the first physical map for this species with 75% of the assembled genome anchored to the chromosomes. Conclusions The AalbF2 genome assembly represents the most up-to-date collective knowledge of the Ae. albopictus genome. These resources represent a foundation to improve understanding of the adaptation potential and the epidemiological relevance of this species and foster the development of innovative control measures.