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Genomes of the dinoflagellate Polarella glacialis encode tandemly repeated single-exon genes with adaptive functions.
Stephens, Timothy G; González-Pech, Raúl A; Cheng, Yuanyuan; Mohamed, Amin R; Burt, David W; Bhattacharya, Debashish; Ragan, Mark A; Chan, Cheong Xin.
Afiliación
  • Stephens TG; Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.
  • González-Pech RA; Present Address: Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA.
  • Cheng Y; Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.
  • Mohamed AR; Present address: Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA.
  • Burt DW; UQ Genomics Initiative, The University of Queensland, Brisbane, QLD, 4072, Australia.
  • Bhattacharya D; Present Address: Faculty of Science, School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW, 2006, Australia.
  • Ragan MA; Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Queensland Bioscience Precinct, Brisbane, QLD, 4067, Australia.
  • Chan CX; UQ Genomics, The University of Queensland, Brisbane, QLD, 4072, Australia.
BMC Biol ; 18(1): 56, 2020 05 24.
Article en En | MEDLINE | ID: mdl-32448240
BACKGROUND: Dinoflagellates are taxonomically diverse and ecologically important phytoplankton that are ubiquitously present in marine and freshwater environments. Mostly photosynthetic, dinoflagellates provide the basis of aquatic primary production; most taxa are free-living, while some can form symbiotic and parasitic associations with other organisms. However, knowledge of the molecular mechanisms that underpin the adaptation of these organisms to diverse ecological niches is limited by the scarce availability of genomic data, partly due to their large genome sizes estimated up to 250 Gbp. Currently available dinoflagellate genome data are restricted to Symbiodiniaceae (particularly symbionts of reef-building corals) and parasitic lineages, from taxa that have smaller genome size ranges, while genomic information from more diverse free-living species is still lacking. RESULTS: Here, we present two draft diploid genome assemblies of the free-living dinoflagellate Polarella glacialis, isolated from the Arctic and Antarctica. We found that about 68% of the genomes are composed of repetitive sequence, with long terminal repeats likely contributing to intra-species structural divergence and distinct genome sizes (3.0 and 2.7 Gbp). For each genome, guided using full-length transcriptome data, we predicted > 50,000 high-quality protein-coding genes, of which ~40% are in unidirectional gene clusters and ~25% comprise single exons. Multi-genome comparison unveiled genes specific to P. glacialis and a common, putatively bacterial origin of ice-binding domains in cold-adapted dinoflagellates. CONCLUSIONS: Our results elucidate how selection acts within the context of a complex genome structure to facilitate local adaptation. Because most dinoflagellate genes are constitutively expressed, Polarella glacialis has enhanced transcriptional responses via unidirectional, tandem duplication of single-exon genes that encode functions critical to survival in cold, low-light polar environments. These genomes provide a foundational reference for future research on dinoflagellate evolution.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Dinoflagelados / Exones / Genoma de Protozoos / Secuencias Repetidas en Tándem / Transcriptoma Idioma: En Revista: BMC Biol Asunto de la revista: BIOLOGIA Año: 2020 Tipo del documento: Article País de afiliación: Australia

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Dinoflagelados / Exones / Genoma de Protozoos / Secuencias Repetidas en Tándem / Transcriptoma Idioma: En Revista: BMC Biol Asunto de la revista: BIOLOGIA Año: 2020 Tipo del documento: Article País de afiliación: Australia
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