Browsing by Author "Unger, Maria F."

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    Evolutionary Dynamics of the Ty3/Gypsy LTR Retrotransposons in the Genome of Anopheles gambiae
    Tubio, Jose M. C.; Tojo, Marta; Bassaganyas, Laia; Escaramis, Georgia; Sharakhov, Igor V.; Sharakhova, Maria V.; Tornador, Cristian; Unger, Maria F.; Naveira, Horacio; Costas, Javier; Besansky, Nora J. (PLOS, 2011-01-24)
    Ty3/gypsy elements represent one of the most abundant and diverse LTR-retrotransposon (LTRr) groups in the Anopheles gambiae genome, but their evolutionary dynamics have not been explored in detail. Here, we conduct an in silico analysis of the distribution and abundance of the full complement of 1045 copies in the updated AgamP3 assembly. Chromosomal distribution of Ty3/gypsy elements is inversely related to arm length, with densities being greatest on the X, and greater on the short versus long arms of both autosomes. Taking into account the different heterochromatic and euchromatic compartments of the genome, our data suggest that the relative abundance of Ty3/gypsy LTRrs along each chromosome arm is determined mainly by the different proportions of heterochromatin, particularly pericentric heterochromatin, relative to total arm length. Additionally, the breakpoint regions of chromosomal inversion 2La appears to be a haven for LTRrs. These elements are underrepresented more than 7-fold in euchromatin, where 33% of the Ty3/gypsy copies are associated with genes. The euchromatin on chromosome 3R shows a faster turnover rate of Ty3/gypsy elements, characterized by a deficit of proviral sequences and the lowest average sequence divergence of any autosomal region analyzed in this study. This probably reflects a principal role of purifying selection against insertion for the preservation of longer conserved syntenyc blocks with adaptive importance located in 3R. Although some Ty3/gypsy LTRrs show evidence of recent activity, an important fraction are inactive remnants of relatively ancient insertions apparently subject to genetic drift. Consistent with these computational predictions, an analysis of the occupancy rate of putatively older insertions in natural populations suggested that the degenerate copies have been fixed across the species range in this mosquito, and also are shared with the sibling species Anopheles arabiensis.
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    Evolutionary superscaffolding and chromosome anchoring to improve Anopheles genome assemblies
    Waterhouse, Robert M.; Aganezov, Sergey; Anselmetti, Yoann; Lee, Jiyoung; Ruzzante, Livio; Reijnders, Maarten J. M. F.; Feron, Romain; Bérard, Sèverine; George, Phillip; Hahn, Matthew W.; Howell, Paul I.; Kamali, Maryam; Koren, Sergey; Lawson, Daniel; Maslen, Gareth; Peery, Ashley; Phillippy, Adam M.; Sharakhova, Maria V.; Tannier, Eric; Unger, Maria F.; Zhang, Simo V.; Alekseyev, Max A.; Besansky, Nora J.; Chauve, Cedric; Emrich, Scott J.; Sharakhov, Igor V. (2020-01-02)
    Background New sequencing technologies have lowered financial barriers to whole genome sequencing, but resulting assemblies are often fragmented and far from ‘finished’. Updating multi-scaffold drafts to chromosome-level status can be achieved through experimental mapping or re-sequencing efforts. Avoiding the costs associated with such approaches, comparative genomic analysis of gene order conservation (synteny) to predict scaffold neighbours (adjacencies) offers a potentially useful complementary method for improving draft assemblies. Results We evaluated and employed 3 gene synteny-based methods applied to 21 Anopheles mosquito assemblies to produce consensus sets of scaffold adjacencies. For subsets of the assemblies, we integrated these with additional supporting data to confirm and complement the synteny-based adjacencies: 6 with physical mapping data that anchor scaffolds to chromosome locations, 13 with paired-end RNA sequencing (RNAseq) data, and 3 with new assemblies based on re-scaffolding or long-read data. Our combined analyses produced 20 new superscaffolded assemblies with improved contiguities: 7 for which assignments of non-anchored scaffolds to chromosome arms span more than 75% of the assemblies, and a further 7 with chromosome anchoring including an 88% anchored Anopheles arabiensis assembly and, respectively, 73% and 84% anchored assemblies with comprehensively updated cytogenetic photomaps for Anopheles funestus and Anopheles stephensi. Conclusions Experimental data from probe mapping, RNAseq, or long-read technologies, where available, all contribute to successful upgrading of draft assemblies. Our evaluations show that gene synteny-based computational methods represent a valuable alternative or complementary approach. Our improved Anopheles reference assemblies highlight the utility of applying comparative genomics approaches to improve community genomic resources.
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    Genome analysis of a major urban malaria vector mosquito, Anopheles stephensi
    Jiang, X.; Peery, A.; Hall, B.; Sharma, A.; Chen, X.-G.; Waterhouse, R. M.; Komissarov, A.; Riehle, M. M.; Shouche, Y.; Sharakhova, Maria V.; Lawson, D.; Pakpour, Nazzy; Arensburger, Peter; Davidson, V. L. M.; Eiglmeier, K.; Emrich, S.; George, P.; Kennedy, R. C.; Mane, S. P.; Maslen, G.; Oringanje, C.; Qi, Y.; Settlage, Robert E.; Tojo, M.; Tubio, J. M. C.; Unger, Maria F.; Wang, B.; Vernick, K. D.; Ribeiro, J. C.; James, A. A.; Michel, K.; Riehle, M. A.; Luckhart, Shirley; Sharakhov, Igor V.; Tu, Zhijian Jake (Biomed Central, 2014-01-01)
    Background: Anopheles stephensi is the key vector of malaria throughout the Indian subcontinent and Middle East and an emerging model for molecular and genetic studies of mosquito-parasite interactions. The type form of the species is responsible for the majority of urban malaria transmission across its range. Results: Here, we report the genome sequence and annotation of the Indian strain of the type form of An. stephensi. The 221 Mb genome assembly represents more than 92% of the entire genome and was produced using a combination of 454, Illumina, and PacBio sequencing. Physical mapping assigned 62% of the genome onto chromosomes, enabling chromosome-based analysis. Comparisons between An. stephensi and An. gambiae reveal that the rate of gene order reshuffling on the X chromosome was three times higher than that on the autosomes. An. stephensi has more heterochromatin in pericentric regions but less repetitive DNA in chromosome arms than An. gambiae. We also identify a number of Y-chromosome contigs and BACs. Interspersed repeats constitute 7.1% of the assembled genome while LTR retrotransposons alone comprise more than 49% of the Y contigs. RNA-seq analyses provide new insights into mosquito innate immunity, development, and sexual dimorphism. Conclusions: The genome analysis described in this manuscript provides a resource and platform for fundamental and translational research into a major urban malaria vector. Chromosome-based investigations provide unique perspectives on Anopheles chromosome evolution. RNA-seq analysis and studies of immunity genes offer new insights into mosquito biology and mosquito-parasite interactions.
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    Genomic analysis of two phlebotomine sand fly vectors of leishmania from the new and old World
    Labbe, Frederic; Abdeladhim, Maha; Abrudan, Jenica; Araki, Alejandra Saori; Araujo, Ricardo N.; Arensburger, Peter; Benoit, Joshua B.; Brazil, Reginaldo Pecanha; Bruno, Rafaela V.; Rivas, Gustavo Bueno da Silva D. S.; de Abreu, Vinicius Carvalho; Charamis, Jason; Coutinho-Abreu, Iliano V.; da Costa-Latge, Samara G.; Darby, Alistair; Dillon, Viv M.; Emrich, Scott J.; Fernandez-Medina, Daniela; Gontijo, Nelder Figueiredo; Flanley, Catherine M.; Gatherer, Derek; Genta, Fernando A.; Gesing, Sandra; Giraldo-Calderon, Gloria I.; Gomes, Bruno; Aguiar, Eric Roberto Guimaraes Rocha; Hamilton, James GC C.; Hamarsheh, Omar; Hawksworth, Mallory; Hendershot, Jacob M.; Hickner, Paul V.; Imler, Jean-Luc; Ioannidis, Panagiotis; Jennings, Emily C.; Kamhawi, Shaden; Karageorgiou, Charikleia; Kennedy, Ryan C.; Krueger, Andreas; Latorre-Estivalis, Jose M.; Ligoxygakis, Petros; Meireles-Filho, Antonio Carlos A.; Minx, Patrick; Miranda, Jose Carlos; Montague, Michael J.; Nowling, Ronald J.; Oliveira, Fabiano; Ortigao-Farias, Joao; Pavan, Marcio G.; Pereira, Marcos Horacio; Pitaluga, Andre Nobrega; Olmo, Roenick Proveti; Ramalho-Ortigao, Marcelo; Ribeiro, Jose MC C.; Rosendale, Andrew J.; Sant'Anna, Mauricio RV V.; Scherer, Steven E.; Secundino, Nagila FC C.; Shoue, Douglas A.; Moraes, Caroline da Silva D. S.; Gesto, Joao Silveira Moledo; Souza, Nataly Araujo; Syed, Zainulabueddin; Tadros, Samuel; Teles-de-Freitas, Rayane; Telleria, Erich L.; Tomlinson, Chad; Traub-Cseko, Yara M.; Marques, Joao Trindade; Tu, Zhijian; Unger, Maria F.; Valenzuela, Jesus; Ferreira, Flavia; de Oliveira, Karla PV V.; Vigoder, Felipe M.; Vontas, John; Wang, Lihui; Weedall, Gareth D.; Zhioua, Elyes; Richards, Stephen; Warren, Wesley C.; Waterhouse, Robert M.; Dillon, Rod J.; McDowell, Mary Ann (Public Library of Science, 2023-04-12)
    Phlebotomine sand flies are of global significance as important vectors of human disease, transmitting bacterial, viral, and protozoan pathogens, including the kinetoplastid parasites of the genus Leishmania, the causative agents of devastating diseases collectively termed leishmaniasis. More than 40 pathogenic Leishmania species are transmitted to humans by approximately 35 sand fly species in 98 countries with hundreds of millions of people at risk around the world. No approved efficacious vaccine exists for leishmaniasis and available therapeutic drugs are either toxic and/or expensive, or the parasites are becoming resistant to the more recently developed drugs. Therefore, sand fly and/or reservoir control are currently the most effective strategies to break transmission. To better understand the biology of sand flies, including the mechanisms involved in their vectorial capacity, insecticide resistance, and population structures we sequenced the genomes of two geographically widespread and important sand fly vector species: Phlebotomus papatasi, a vector of Leishmania parasites that cause cutaneous leishmaniasis, (distributed in Europe, the Middle East and North Africa) and Lutzomyia longipalpis, a vector of Leishmania parasites that cause visceral leishmaniasis (distributed across Central and South America). We categorized and curated genes involved in processes important to their roles as disease vectors, including chemosensation, blood feeding, circadian rhythm, immunity, and detoxification, as well as mobile genetic elements. We also defined gene orthology and observed micro-synteny among the genomes. Finally, we present the genetic diversity and population structure of these species in their respective geographical areas. These genomes will be a foundation on which to base future efforts to prevent vector-borne transmission of Leishmania parasites.
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    Genomic insights into the Ixodes scapularis tick vector of Lyme disease
    Gulia-Nuss, Monika; Nuss, Andrew B.; Meyer, Jason M.; Sonenshine, Daniel E.; Roe, R. Michael; Waterhouse, Robert M.; Sattelle, David B.; de la Fuente, Jose; Ribeiro, Jose M.; Megy, Karine; Thimmapuram, Jyothi; Miller, Jason R.; Walenz, Brian P.; Koren, Sergey; Hostetler, Jessica B.; Thiagarajan, Mathangi; Joardar, Vinita S.; Hannick, Linda I.; Bidwell, Shelby; Hammond, Martin P.; Young, Sarah; Zeng, Qiandong; Abrudan, Jenica L.; Almeida, Francisca C.; Ayllon, Nieves; Bhide, Ketaki; Bissinger, Brooke W.; Bonzon-Kulichenko, Elena; Buckingham, Steven D.; Caffrey, Daniel R.; Caimano, Melissa J.; Croset, Vincent; Driscoll, Timothy; Gilbert, Don; Gillespie, Joseph J.; Giraldo-Calderon, Gloria I.; Grabowski, Jeffrey M.; Jiang, David; Khalil, Sayed M. S.; Kim, Donghun; Kocan, Katherine M.; Koci, Juraj; Kuhn, Richard J.; Kurtti, Timothy J.; Lees, Kristin; Lang, Emma G.; Kennedy, Ryan C.; Kwon, Hyeogsun; Perera, Rushika; Qi, Yumin; Radolf, Justin D.; Sakamoto, Joyce M.; Sanchez-Gracia, Alejandro; Severo, Maiara S.; Silverman, Neal; Simo, Ladislav; Tojo, Marta; Tornador, Cristian; Van Zee, Janice P.; Vazquez, Jesus; Vieira, Filipe G.; Villar, Margarita; Wespiser, Adam R.; Yang, Yunlong; Zhu, Jiwei; Arensburger, Peter; Pietrantonio, Patricia V.; Barker, Stephen C.; Shao, Renfu; Zdobnov, Evgeny M.; Hauser, Frank; Grimmelikhuijzen, Cornelis J. P.; Park, Yoonseong; Rozas, Julio; Benton, Richard; Pedra, Joao H. F.; Nelson, David R.; Unger, Maria F.; Tubio, Jose M. C.; Tu, Zhijian Jake; Robertson, Hugh M.; Shumway, Martin; Sutton, Granger; Wortman, Jennifer R.; Lawson, Daniel; Wikel, Stephen K.; Nene, Vishvanath M.; Fraser, Claire M.; Collins, Frank H.; Birren, Bruce; Nelson, Karen E.; Caler, Elisabet; Hill, Catherine A. (Springer Nature, 2016-02)
    Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing similar to 57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick-host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host 'questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.
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    A standard cytogenetic map of Culex quinquefasciatus polytene chromosomes in application for fine-scale physical mapping
    Unger, Maria F.; Sharakhova, Maria V.; Harshbarger, Adam J.; Glass, Patrick; Collins, Frank H. (2015-06-06)
    Background Southern house mosquito Culex quinquefasciatus belongs to the C. pipiens cryptic species complex, with global distribution and unclear taxonomy. Mosquitoes of the complex can transmit human and animal pathogens, such as filarial worm, West Nile virus and avian malarial Plasmodium. Physical gene mapping is crucial to understanding genome organization, function, and systematic relationships of cryptic species, and is a basis for developing new vector control strategies. However, physical mapping was not established previously for Culex due to the lack of well-structured polytene chromosomes. Methods Inbreeding was used to diminish inversion polymorphism and asynapsis of chromosomal homologs. Identification of larvae of the same developmental stage using the shape of imaginal discs allowed achievement of uniformity in chromosomal banding pattern. This together with high-resolution phase-contrast photography enabled the development of a cytogenetic map. Fluorescent in situ hybridization was used for gene mapping. Results A detailed cytogenetic map of C. quinquefasciatus polytene chromosomes was produced. Landmarks for chromosome recognition and cytological boundaries for two inversions were identified. Locations of 23 genes belonging to 16 genomic supercontigs, and 2 cDNA were established. Six supercontigs were oriented and one was found putatively misassembled. The cytogenetic map was linked to the previously developed genetic linkage groups by corresponding positions of 2 genetic markers and 10 supercontigs carrying genetic markers. Polytene chromosomes were numbered according to the genetic linkage groups. Conclusions This study developed a new standard cytogenetic photomap of the polytene chromosomes for C. quinquefasciatus and was applied for the fine-scale physical mapping. It allowed us to infer chromosomal position of 1333 of annotated genes belonging to 16 genomic supercontigs and find orientation of 6 of these supercontigs; the new cytogenetic and previously developed genetic linkage maps were integrated based on 12 matches. The map will further assist in finding chromosomal position of the medically important and other genes, contributing into improvement of the genome assembly. Better assembled C. quinquefasciatus genome can serve as a reference for studying other vector species of C. pipiens complex and will help to resolve their taxonomic relationships. This, in turn, will contribute into future development of vector and disease control strategies.
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    Update of the Anopheles gambiaePEST genome assembly
    Sharakhova, Maria V.; Hammond, Martin P.; Lobo, Neil F.; Krzywinski, Jaroslaw; Unger, Maria F.; Hillenmeyer, Maureen E.; Bruggner, Robert V.; Birney, Ewan; Collins, Frank H. (2007-01-08)
    Background The genome of Anopheles gambiae, the major vector of malaria, was sequenced and assembled in 2002. This initial genome assembly and analysis made available to the scientific community was complicated by the presence of assembly issues, such as scaffolds with no chromosomal location, no sequence data for the Y chromosome, haplotype polymorphisms resulting in two different genome assemblies in limited regions and contaminating bacterial DNA. Results Polytene chromosome in situ hybridization with cDNA clones was used to place 15 unmapped scaffolds (sizes totaling 5.34 Mbp) in the pericentromeric regions of the chromosomes and oriented a further 9 scaffolds. Additional analysis by in situ hybridization of bacterial artificial chromosome (BAC) clones placed 1.32 Mbp (5 scaffolds) in the physical gaps between scaffolds on euchromatic parts of the chromosomes. The Y chromosome sequence information (0.18 Mbp) remains highly incomplete and fragmented among 55 short scaffolds. Analysis of BAC end sequences showed that 22 inter-scaffold gaps were spanned by BAC clones. Unmapped scaffolds were also aligned to the chromosome assemblies in silico, identifying regions totaling 8.18 Mbp (144 scaffolds) that are probably represented in the genome project by two alternative assemblies. An additional 3.53 Mbp of alternative assembly was identified within mapped scaffolds. Scaffolds comprising 1.97 Mbp (679 small scaffolds) were identified as probably derived from contaminating bacterial DNA. In total, about 33% of previously unmapped sequences were placed on the chromosomes. Conclusion This study has used new approaches to improve the physical map and assembly of the A. gambiae genome.