Search bioRxiv⌕ Search

Biology subjects

Bourne, D.

Publications and source records attributed to Bourne, D..

2 recordsLinked to original sources

Extended genomic regions flanking ultraconserved elements allow efficient species identification and intraspecific diversity assessment in coral

Genetically informed conservation is critically important to ensure that interventions benefit the population of interest. In corals, preserving genetic diversity and accurate species identification are crucial for the sexual propagation. While various methods exist for species identification and measuring intraspecific variation, obtaining and analysing molecular data that enables rapid yet informed decisions on broodstock choice and progeny quality assurance remains challenging. Here we present a novel approach towards resource effective intraspecific genetic profiling by targeting extended genomic regions around ultra-conserved elements (UCEs). By sorting loci by parsimony informativeness and using a locus window size as small as 5000 bp upstream and downstream of the UCE, we identified a subset of 500 UCE-associated loci that can accurately resolve phylogenetic relationships among species and assess intraspecific variation with accuracy comparable to a whole-genome dataset, while. This method was validated using existing population genomic data from six species of staghorn coral (Acropora hyacinthus, Acropora tersa, Acropora pectinata, Acropora sp. "VI-3", Acropora kenti and Acropora cf. spathulata). The phylogeny produced by the UCE subset is congruent with the phylogeny based on complete data. With the moderate number and length of target genomic region sizes providing a balance between resolution and sequencing effort, this study provides a proof-of-concept approach towards developing fast, scalable, and cost-effective workflows using a real-time long-read sequencers such as Oxford Nanopore Technologies. The methodology has the broad potential to be applied to support genetic assessment across taxa where taxonomic uncertainty is common, improving confidence in experimental frameworks and conservation decisions.

genomics↗

Transcriptomic insights into the establishment of coral-algal symbioses from the symbiont perspective

Despite the ecological significance of the mutualistic relationship between Symbiodiniaceae and reef-building corals, the molecular machinery underpinning the establishment of this relationship is not well understood. This is especially true of the symbiont side, as previous attempts to understand the interaction between coral larvae and Symbiodiniaceae have focused nearly exclusively on the host. In the current study, Acropora tenuis planula larvae were exposed to a compatible strain of Symbiodiniaceae (Cladocopium) and the transcriptomic landscape of the symbiont profiled at 3, 12, 48 and 72 h post-exposure using RNA-Seq. The transcriptomic response of Cladocopium to the symbiotic state was complex, the most obvious feature being an extensive and generalised downregulation of gene expression. Included in this \"symbiosis-derived transcriptional repression\" were a range of stress response and immune-related genes. In contrast, genes implicated in metabolism were upregulated in the symbiotic state. Consistent with previous ecological studies, this transcriptomic response of Cladocopium implied that active translocation of metabolites to the host occurred, and thus that the mutualistic relationship can be established at the larval stage. This study provides novel insights into the transcriptomic remodelling that occurs in Symbiodiniaceae, with important implications for understanding the establishment of symbiosis between corals and their dinoflagellate partners.

genomics↗