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Browsing by Author "Black, William C."

Now showing 1 - 4 of 4
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    Dual African Origins of Global Aedes aegypti s.l. Populations Revealed by Mitochondrial DNA
    Moore, Michelle; Sylla, Massamba; Goss, Laura; Burugu, Marion Warigia; Sang, Rosemary; Kamau, Luna W.; Kenya, Eucharia Unoma; Bosio, Chris; de Lourdes Munoz, Maria; Sharakhova, Maria V.; Black, William C. (PLOS, 2013-04)
    Background: Aedes aegypti is the primary global vector to humans of yellow fever and dengue flaviviruses. Over the past 50 years, many population genetic studies have documented large genetic differences among global populations of this species. These studies initially used morphological polymorphisms, followed later by allozymes, and most recently various molecular genetic markers including microsatellites and mitochondrial markers. In particular, since 2000, fourteen publications and four unpublished datasets have used sequence data from the NADH dehydrogenase subunit 4 mitochondrial gene to compare Ae. aegypti collections and collectively 95 unique mtDNA haplotypes have been found. Phylogenetic analyses in these many studies consistently resolved two clades but no comprehensive study of mtDNA haplotypes have been made in Africa, the continent in which the species originated. Methods and Findings: ND4 haplotypes were sequenced in 426 Ae. aegypti s.l. from Senegal, West Africa and Kenya, East Africa. In Senegal 15 and in Kenya 7 new haplotypes were discovered. When added to the 95 published haplotypes and including 6 African Aedes species as outgroups, phylogenetic analyses showed that all but one Senegal haplotype occurred in a basal clade while most East African haplotypes occurred in a second clade arising from the basal clade. Globally distributed haplotypes occurred in both clades demonstrating that populations outside Africa consist of mixtures of mosquitoes from both clades. Conclusions: Populations of Ae. aegypti outside Africa consist of mosquitoes arising from one of two ancestral clades. One clade is basal and primarily associated with West Africa while the second arises from the first and contains primarily mosquitoes from East Africa
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    Improved reference genome of Aedes aegypti informs arbovirus vector control
    Matthews, Benjamin J.; Dudchenko, Olga; Kingan, Sarah B.; Koren, Sergey; Antoshechkin, Igor; Crawford, Jacob E.; Glassford, William J.; Herre, Margaret; Redmond, Seth N.; Rose, Noah H.; Weedall, Gareth D.; Wu, Yang; Batra, Sanjit S.; Brito-Sierra, Carlos A.; Buckingham, Steven D.; Campbell, Corey L.; Chan, Saki; Cox, Eric; Evans, Benjamin R.; Fansiri, Thanyalak; Filipovic, Igor; Fontaine, Albin; Gloria-Soria, Andrea; Hall, Richard; Joardar, Vinita S.; Jones, Andrew K.; Kay, Raissa G. G.; Kodali, Vamsi K.; Lee, Joyce; Lycett, Gareth J.; Mitchell, Sara N.; Muehling, Jill; Murphy, Michael R.; Omer, Arina D.; Partridge, Frederick A.; Peluso, Paul; Aiden, Aviva Presser; Ramasamy, Vidya; Rasic, Gordana; Roy, Sourav; Saavedra-Rodriguez, Karla; Sharan, Shruti; Sharma, Atashi; Smith, Melissa Laird; Turner, Joe; Weakley, Allison M.; Zhao, Zhilei; Akbari, Omar S.; Black, William C.; Cao, Han; Darby, Alistair C.; Hill, Catherine A.; Johnston, J. Spencer; Murphy, Terence D.; Raikhel, Alexander S.; Sattelle, David B.; Sharakhov, Igor V.; White, Bradley J.; Zhao, Li; Aiden, Erez Lieberman; Mann, Richard S.; Lambrechts, Louis; Powell, Jeffrey R.; Sharakhova, Maria V.; Tu, Zhijian Jake; Robertson, Hugh M.; McBride, Carolyn S.; Hastic, Alex R.; Korlach, Jonas; Neafsey, Daniel E.; Phillippy, Adam M.; Vosshall, Leslie B. (2018-11-22)
    Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector.
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    An Integrated Linkage, Chromosome, and Genome Map for the Yellow Fever Mosquito Aedes aegypti
    Timoshevskiy, Vladimir A.; Severson, David W.; deBruyn, Becky S.; Black, William C.; Sharakhov, Igor V.; Sharakhova, Maria V. (PLOS, 2013-02-01)
    Background: Aedes aegypti, the yellow fever mosquito, is an efficient vector of arboviruses and a convenient model system for laboratory research. Extensive linkage mapping of morphological and molecular markers localized a number of quantitative trait loci (QTLs) related to the mosquito’s ability to transmit various pathogens. However, linking the QTLs to Ae. aegypti chromosomes and genomic sequences has been challenging because of the poor quality of polytene chromosomes and the highly fragmented genome assembly for this species. Methodology/Principal Findings: Based on the approach developed in our previous study, we constructed idiograms for mitotic chromosomes of Ae. aegypti based on their banding patterns at early metaphase. These idiograms represent the first cytogenetic map developed for mitotic chromosomes of Ae. aegypti. One hundred bacterial artificial chromosome clones carrying major genetic markers were hybridized to the chromosomes using fluorescent in situ hybridization. As a result, QTLs related to the transmission of the filarioid nematode Brugia malayi, the avian malaria parasite Plasmodium gallinaceum, and the dengue virus, as well as sex determination locus and 183 Mbp of genomic sequences were anchored to the exact positions on Ae. aegypti chromosomes. A linear regression analysis demonstrated a good correlation between positions of the markers on the physical and linkage maps. As a result of the recombination rate variation along the chromosomes, 12 QTLs on the linkage map were combined into five major clusters of QTLs on the chromosome map. Conclusion: This study developed an integrated linkage, chromosome, and genome map—iMap—for the yellow fever mosquito. Our discovery of the localization of multiple QTLs in a few major chromosome clusters suggests a possibility that the transmission of various pathogens is controlled by the same genomic loci. Thus, the iMap will facilitate the identification of genomic determinants of traits responsible for susceptibility or refractoriness of the mosquito to diverse pathogens.
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    Reproductive Incompatibility Involving Senegalese Aedes aegypti (L) Is Associated with Chromosome Rearrangements
    Dickson, Laura B.; Sharakhova, Maria V.; Timoshevskiy, Vladimir A.; Fleming, Karen L.; Caspary, Alex; Sylla, Massamba; Black, William C. (PLOS, 2016-04)
    Aedes aegypti, the primary vector of dengue, yellow fever and Zika flaviviruses, consists of at least two subspecies. Aedes aegypti (Aaa) is light in color, has pale scales on the first abdominal tergite, oviposits in artificial containers, and preferentially feeds on humans. Aedes aegypti formosus (Aaf), has a dark cuticle, is restricted to sub-Saharan Africa, has no pale scales on the first abdominal tergite and frequently oviposits in natural containers. Scale patterns correlate with cuticle color in East Africa but not in Senegal, West Africa where black cuticle mosquitoes display a continuum of scaling patterns and breed domestically indoors. An earlier laboratory study did not indicate any pre- or postzygotic barriers to gene flow between Aaa and Aaf in East Africa. However, similar attempts to construct F-1 intercross families between Aaa laboratory strains and Senegal Ae. aegypti (SenAae) failed due to poor F-1 oviposition and low F-2 egg-to-adult survival. Insemination and assortative mating experiments failed to identify prezygotic mating barriers. Backcrosses were performed to test for postzygotic isolation patterns consistent with Haldane's rule modified for species, like Aedes, that have an autosomal sex determining locus (SDL). Egg-pupal survival was predicted to be low in females mated to hybrid F-1 males but average when a male mates with a hybrid F-1 female. Survival was in fact significantly reduced when females mated to hybrid males but egg-pupal survival was significantly increased when males were mated to hybrid F-1 females. These observations are therefore inconclusive with regards to Haldane's rule. Basic cytogenetic analyses and Fluorescent In Situ Hybridization (FISH) experiments were performed to compare SenAae strains with the IB12 strain of Aaa that was used for genome sequencing and physical mapping. Some SenAae strains had longer chromosomes than IB12 and significantly different centromeric indices on chromosomes 1 and 3. DAPI staining was used to identify AT-rich regions, chromomycin A3 following pretreatment with barium hydroxide stained for GC-rich regions and stained the ribosomal RNA locus and YOYO-1 was used to test for differential staining. Chromosome patterns in SenAae strains revealed by these three stains differed from those in IB12. For FISH, 40 BAC clones previously physically mapped on Aaa chromosomes were used to test for chromosome rearrangements in SenAae relative to IB12. Differences in the order of markers identified two chromosomal rearrangements between IB12 and SenAae strains. The first rearrangement involves two overlapping pericentric (containing the centromere) inversions in chromosome 3 or an insertion of a large fragment into the 3q arm. The second rearrangement is close to the centromere on the p arm of chromosome 2. Linkage analysis of the SDL and the white-eye locus identified a likely chromosomal rearrangement on chromosome 1. The reproductive incompatibility observed within SenAae and between SenAae and Aaa may be generally associated with chromosome rearrangements on all three chromosomes and specifically caused by pericentric inversions on chromosomes 2 and 3.