Massive genome reduction occurred prior to the origin of coral algal symbionts

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: March 25, 2023

Abstract Dinoflagellates in the Family Symbiodiniaceae (Order Suessiales) are diverse, predominantly symbiotic lineages that associate with taxa such as corals and jellyfish. Their ancestor is believed to have been free-living, establishment of symbiosis (i.e., symbiogenesis) hypothesised occurred multiple times during evolution. Among taxa, genus Effrenium an early diverging, free-living lineage phylogenetically positioned between two robustly supported groups genera within which emerged. The lack symbiogenesis suggests ancestral features may retained this lineage. Here we present de novo assembled genomes associated transcriptome data from three isolates voratum . We compared (1.2-1.9 Gbp size) gene those 16 other outgroup dinoflagellates. Surprisingly, find genome reduction, often a lifestyle, predates origin Symbiodiniaceae. postulate adaptation extreme habitat (e.g., Polarella glacialis ) or life oligotrophic conditions resulted Suessiales having haploid size < 2Gbp, was (or reduced) among all extant algae Nonetheless, our reveal lifestyle distinguishes vis-à-vis their longer introns, more-extensive mRNA editing, fewer (∼30%) lineage-specific families, lower (∼10%) level pseudogenisation. These results demonstrate how reduction versus lifestyles intersect, driven diversification evolution

Language: Английский

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Whole genome population structure of North Atlantic kelp confirms high‐latitude glacial refugia

Molecular Ecology, Journal Year: 2022, Volume and Issue: 31(24), P. 6473 - 6488

Published: Oct. 6, 2022

Coastal refugia during the Last Glacial Maximum (~21,000 years ago) have been hypothesized at high latitudes in North Atlantic, suggesting marine populations persisted through cycles of glaciation and are potentially adapted to local environments. Here, whole-genome sequencing was used test whether Atlantic coastal kelp Alaria esculenta survived area southwestern Greenland Maximum. We present first annotated genome for A. call variant positions 54 individuals from Canada, Greenland, Faroe Islands, Norway Ireland. Differentiation across reflected ~1.9 million single nucleotide polymorphisms, which further revealed mixed ancestry Islands between putative Greenlandic European lineages. Time-calibrated organellar phylogenies suggested were established last interglacial period more than 100,000 ago, that population probably following Patterns statistics, including diversity, minor allele frequencies, heterozygosity linkage disequilibrium decay, nonetheless reduced Canadian small effective sizes most recent glaciation. Functional differentiation exon read coverage, expansions unique 337 exons representing 162 genes, a modest degree loss (103 56 genes). Altogether, our genomic results provide strong evidence resilient past climatic fluctuations related glaciations high-latitude already conditions as result.

Language: Английский

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Genomic analysis of an ultrasmall freshwater green alga, Medakamo hakoo

Communications Biology, Journal Year: 2023, Volume and Issue: 6(1)

Published: Jan. 23, 2023

Ultrasmall algae have attracted the attention of biologists investigating basic mechanisms underlying living systems. Their potential as effective organisms for producing useful substances is also interest in bioindustry. Although genomic information indispensable elucidating metabolism and promoting molecular breeding, many ultrasmall remain genetically uncharacterized. Here, we present nuclear genome sequence an green alga freshwater habitats, Medakamo hakoo. Evolutionary analyses suggest that this species belongs to a new genus within class Trebouxiophyceae. Sequencing revealed its genome, comprising 15.8 Mbp 7629 genes, among smallest known genomes Viridiplantae. Its has relatively few genes associated with genetic processing, basal transcription factors, RNA transport. Comparative 1263 orthogroups were shared 15 from distinct phylogenetic lineages. The gene sets will enable identification essential algal cellular functions.

Language: Английский

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Whole‐genome sequencing reveals forgotten lineages and recurrent hybridizations within the kelp genus Alaria (Phaeophyceae)

Journal of Phycology, Journal Year: 2021, Volume and Issue: 57(6), P. 1721 - 1738

Published: Sept. 12, 2021

The genomic era continues to revolutionize our understanding of the evolution biodiversity. In phycology, emphasis remains on assembling nuclear and organellar genomes, leaving full potential datasets answer long-standing questions about biodiversity largely unexplored. Here, we used whole-genome sequencing (WGS) survey species diversity in kelp genus Alaria, compare phylogenetic signals across specifically test whether phylogenies behave like trees or networks. Genomes were sequenced from global distribution Alaria (including crassifolia, A. praelonga, crispa, marginata, esculenta), representing over 550 GB data 2.2 billion paired reads. Genomic retrieved 3,814 4,536 single-nucleotide polymorphisms (SNPs) for mitochondrial chloroplast respectively, upwards 148,542 high-quality SNPs. WGS revealed an Arctic lineage which hypothesize represents synonymized taxon grandifolia. SNP also inconsistent topologies compartments, hybridization (i.e., networks) between Pacific putative grandifolia, some lineages marginata complex. Our analysis demonstrates advance beyond amplicon sequencing, that is potentially important mechanism contributing novel within Alaria. We emphasize importance surveying such models mixed ancestry become integrated into evolutionary taxonomic understanding.

Language: Английский

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Cross-feeding among microalgae facilitates nitrogen recovery at low C/N

Environmental Research, Journal Year: 2022, Volume and Issue: 211, P. 113052 - 113052

Published: March 9, 2022

Language: Английский

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