25 research outputs found

    Zebrafish homologs of 16p11.2, a genomic region associated with brain disorders, are active during brain development, and include two deletion dosage sensor genes

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    Deletion or duplication of one copy of the human 16p11.2 interval is tightly associated with impaired brain function, including autism spectrum disorders (ASDs), intellectual disability disorder (IDD) and other phenotypes, indicating the importance of gene dosage in this copy number variant region (CNV). The core of this CNV includes 25 genes; however, the number of genes that contribute to these phenotypes is not known. Furthermore, genes whose functional levels change with deletion or duplication (termed 'dosage sensors'), which can associate the CNV with pathologies, have not been identified in this region. Using the zebrafish as a tool, a set of 16p11.2 homologs was identified, primarily on chromosomes 3 and 12. Use of 11 phenotypic assays, spanning the first 5 days of development, demonstrated that this set of genes is highly active, such that 21 out of the 22 homologs tested showed loss-of-function phenotypes. Most genes in this region were required for nervous system development - impacting brain morphology, eye development, axonal density or organization, and motor response. In general, human genes were able to substitute for the fish homolog, demonstrating orthology and suggesting conserved molecular pathways. In a screen for 16p11.2 genes whose function is sensitive to hemizygosity, the aldolase a (aldoaa) and kinesin family member 22 (kif22) genes were identified as giving clear phenotypes when RNA levels were reduced by ~50%, suggesting that these genes are deletion dosage sensors. This study leads to two major findings. The first is that the 16p11.2 region comprises a highly active set of genes, which could present a large genetic target and might explain why multiple brain function, and other, phenotypes are associated with this interval. The second major finding is that there are (at least) two genes with deletion dosage sensor properties among the 16p11.2 set, and these could link this CNV to brain disorders such as ASD and IDD.Simons Foundation (Grant Number 95091

    Four new species of Brueelia Kéler, 1936 (Phthiraptera: Ischnocera) from African hosts, with a redescription of Nirmus bicurvatus Piaget, 1880

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    Four new species of Brueelia Kéler, 1936 are described and illustrated. All of them parasitize African endemic host species in the families Passeridae, Ploceidae, and Estrildidae (Passeriformes). They are: Brueelia pofadderensis sp. nov. ex Passer melanurus damarensis Reichenow, 1902 and P. m. vicinus Clancey, 1958; B. semiscalaris sp. nov. ex Granatina granatina (Linnaeus, 1758); B. sima sp. nov. ex Malimbus nitens (Gray, 1831); B. terpsichore sp. nov. ex Euplectes jacksoni (Sharpe, 1891) and E. progne delamerei (Shelley, 1903). In addition, Brueelia bicurvata (Piaget, 1880) is redescribed and reillustrated from non-type material. A summary of all published records of lice in the Brueelia complex from Africa since 1980 is provided. We also estimate the unknown diversity of African species of Brueelia based on an index of host specificity calculated for each host family independently. The unknown diversity is estimated to be over 1000 species of Brueelia from African hosts, compared to the < 50 species in this genus currently recorded from Africa

    Four new species of Brueelia Kéler, 1936 (Phthiraptera: Ischnocera) from African hosts, with a redescription of Nirmus bicurvatus Piaget, 1880

    No full text
    Four new species of Brueelia Kéler, 1936 are described and illustrated. All of them parasitize African endemic host species in the families Passeridae, Ploceidae, and Estrildidae (Passeriformes). They are: Brueelia pofadderensis sp. nov. ex Passer melanurus damarensis Reichenow, 1902 and P. m. vicinus Clancey, 1958; B. semiscalaris sp. nov. ex Granatina granatina (Linnaeus, 1758); B. sima sp. nov. ex Malimbus nitens (Gray, 1831); B. terpsichore sp. nov. ex Euplectes jacksoni (Sharpe, 1891) and E. progne delamerei (Shelley, 1903). In addition, Brueelia bicurvata (Piaget, 1880) is redescribed and reillustrated from non-type material. A summary of all published records of lice in the Brueelia complex from Africa since 1980 is provided. We also estimate the unknown diversity of African species of Brueelia based on an index of host specificity calculated for each host family independently. The unknown diversity is estimated to be over 1000 species of Brueelia from African hosts, compared to the < 50 species in this genus currently recorded from Africa

    Figs 11–15 in Four new species of Brueelia Kéler, 1936 (Phthiraptera: Ischnocera) from African hosts, with a redescription of Nirmus bicurvatus Piaget, 1880

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    Figs 11–15. Brueelia semiscalaris sp. nov. ex Granatina granatina (Linnaeus, 1766). 11–14. ♂, holotype (NHML 1956-561). 11. Head, dorsal and ventral views; a–b. Antennae from ♀, dorsal and ventral views. 12. Genitalia, dorsal view. 13. Mesosome, ventral view. 14. Paramere, dorsal view. 15. ♀, subgenital plate and vulval margin, ventral view

    Insect ectoparasites from wild passerine birds in the Azores Islands

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    A total of 266 wild passerine birds (Passeriformes) representing eight species and nine subspecies from three islands of the Archipelago of the Azores were examined for ectoparasites. Two species of louse-flies Ornithomya avicularia and Ornithoica turdi (Diptera: Hippoboscidae), three species of fleas Ceratophyllus gallinae, Ceratophyllus sp. and Dasypsyllus gallinulae (Siphonaptera: Ceratophyllidae), and 11 species of chewing lice belonging to the genera Menacanthus, Myrsidea (Phthiraptera: Menoponidae), Ricinus (Phthiraptera: Ricinidae), Brueelia, Guimaraesiella, Philopterus, Sturnidoecus and Turdinirmus (Phthiraptera: Philopteridae) were recorded. At least one species of ectoparasite was found on 114 birds of six species. Guimaraesiella tovornikae and Myrsidea sylviae from Sylvia atricapilla are redescribed. Records of Ceratophyllus sp. and Sturnidoecus sp. from Turdus merula represent new parasite-host associations. Phoresy of Guimaraesiella amsel on Ornithoica turdi was also found. Parasitological parameters such as prevalence, intensity and abundance and geographic distribution of recorded ectoparasites are provided
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