Biology subjects

Quattrini, A. M.

Publications and source records attributed to Quattrini, A. M..

10 recordsLinked to original sources

bioRxiv2026

High Connectivity, Local Signatures: Genomic and Otolith Evidence from Reef-Associated Snappers.

Connectivity in reef-associated fishes emerges from processes operating across multiple spatial and temporal scales, yet these processes are rarely evaluated jointly. Here, we integrated genome-wide single-nucleotide polymorphisms (SNPs) data and otolith elemental signatures to examine connectivity in Red Snapper (Lutjanus campechanus) and Vermilion Snapper (Rhomboplites aurorubens) across 14 reefs and banks from the Flower Garden Banks National Marine Sanctuary and neighboring banks to the east. We tested whether genomic variation revealed population structure across geographic and depth gradients (shallow, upper mesophotic, and lower mesophotic), whether otolith chemistry captured fine-scale site-specific patterns of environmental exposure and habitat use not resolved by genetic markers alone, and how these complementary signals related to spatial variation in age structure and growth dynamics. Genome-wide SNP data revealed little detectable spatial genetic structure across the sampled banks in either species. In contrast, otolith microchemistry revealed pronounced site-associated environmental structuring, indicating that individuals experience localized habitat conditions within a regionally connected system. Red Snapper exhibited otolith signatures consistent with reef-associated environments, whereas Vermilion Snapper showed more variable elemental signatures, indicating exposure to a broader or more heterogeneous range of habitats. Spatial variation in age structure and growth provided additional demographic context, indicating that local differences among banks can emerge despite weak genomic differentiation. Together, these results show that fine-scale ecological and demographic differentiation can exist within a genetically connected system and that otolith chemistry provides critical information on post-settlement processes at scales not captured by genetic markers alone. By linking regional genomic connectivity with otolith-derived habitat signatures and demographic variation, this integrative framework provides a more comprehensive basis for understanding resilience and informing fisheries management in shelf-edge reef systems.

ecology↗

bioRxiv2024

New mitochondrial gene order arrangements and evolutionary implications in the subclass Octocorallia

The complete mitochondrial genomes of octocorals typically range from 18.5 kb to 20.5 kb in length, and include 14 protein coding genes (PCGs), two ribosomal RNA genes and one tRNA. To date seven different gene orders (A-G) have been described, yet comprehensive investigations of the actual number of arrangements, as well as comparative analyses and evolutionary reconstructions of mitochondrial genome evolution within the whole subclass Octocorallia have been often overlooked. Here we considered the complete mitochondrial genomes available for octocorals and explored their structure and gene order variability. Our results updated the actual number of mitochondrial gene order arrangements so far known for octocorals from seven to twelve, and allowed us to explore and preliminarily discuss the role of some of the structural and functional factors in the mitogenomes. We performed comparative mitogenomic analyses on the existing and novel octocoral gene orders, considering different mitogenomic structural features such as genome size, GC percentage, AT- and GC-skewness. The mitochondrial gene order history mapped on a recently published nuclear loci phylogeny showed that the most common rearrangement events in octocorals are inversions, and that the mitochondrial genome evolution in the subclass is discontinuous, with rearranged gene orders restricted only to some regions of the tree. We believe that different rearrangement events arose independently and most likely that new gene orders, instead of being derived from other rearranged orders, came from the ancestral and most common gene order. Finally, our data demonstrate how the study of mitochondrial gene orders can be used to explore the evolution of octocorals and in some cases can be used to assess the phylogenetic placement of certain taxa.

genomics↗

bioRxiv2023

Nuclear eDNA Metabarcoding Primers for Anthozoan Coral Biodiversity Assessment

The distributions of anthozoan corals are under-characterized due to their wide bathymetric range, occurrences in remote locales, and difficulties of identification from morphology alone. Environmental DNA (eDNA) sequencing promises to be a non-invasive strategy to complement conventional approaches for mapping and monitoring coral communities. Primers for eDNA meta-barcoding have been designed to amplify nuclear and mitochondrial DNA barcodes in shallow scleractinians and mitochondrial MutS in deep-sea octocorals. However, a comprehensive method for eDNA meta-barcoding from all anthozoan corals, including black corals, has not been developed. We leveraged a sequence database of global coral collections, from shallow water to the deep sea, to design new PCR primers for coral eDNA sequencing that target the 28S rRNA gene. We tested the performance of these primers by amplifying and sequencing eDNA from water samples collected in the Gulf of Mexico near mesophotic and deep-sea corals that were also imaged, sampled, and sequenced. Sequencing libraries produced using the primers were highly enriched in coral eDNA, with up to 99.8% of the reads originating from corals. Further, the 28S barcode amplified using the primers distinguished coral genera. We recovered amplicon sequencing variants (ASVs) identical to DNA barcodes derived from Sanger sequencing and genome skimming of corals sampled at the same field sites. This new eDNA meta-barcoding strategy permits targeted eDNA sequencing of black corals, octocorals, and scleractinians at sites where they co-occur and expands our current toolkit for mapping and monitoring coral communities in shallow coral reefs and the deep sea.

ecology↗

bioRxiv2023

Skimming genomes for systematics and DNA barcodes of corals

1: Numerous genomic methods developed over the past two decades have enabled the discovery and extraction of orthologous loci to help resolve phylogenetic relationships across various taxa and scales. Genome skimming (or low-coverage whole genome sequencing) remains a low-cost, promising method to not only extract high-copy loci, but also 100s to 1000s of phylogenetically informative single-copy nuclear loci (e.g., ultraconserved elements [UCEs] and exons) from contemporary and historical museum samples. The subphylum Anthozoa, which includes important ecosystem engineers (e.g., stony corals, black corals, anemones and octocorals) in the marine environment, is in critical need of phylogenetic resolution and thus might benefit from a genome-skimming approach. 2: Genome skimming was conducted on 242 hexacorals and octocorals collected from 1890 to 2022. Using previously developed target-capture baitsets, we bioinformatically obtained UCEs and exons from the genome-skimming data and incorporated them with data from previously published target-capture studies. We also extracted partial to whole mitogenomes and nuclear rRNA genes from the skim data. 3: The mean number of UCE and exon loci extracted from the genome skimming data was 1,837 {+/-} 662 SD for octocorals and 1,422 {+/-} 720 loci for hexacorals; phylogenetic relationships were well resolved within each class. A mean of 1,422 {+/-} 720 loci were obtained from the historical museum specimens, with 1,253 loci recovered from the oldest specimen collected in 1886 and 1,336 loci recovered from a holotype. The nuclear rRNA genes and the majority of mitochondrial genes were successfully obtained from >95% of samples. Out of 99 circularized mitogenomes, 88% were recovered in samples from which we obtained >15M paired-end (PE) reads (>30M total reads); there was more variability in whether mitogenomes were circularized or not in samples with <15M PE reads. 4: Bioinformatically pulling UCEs, exons, mitochondrial genomes, and nuclear rRNA genes from genome skimming is a viable and low-cost option for phylogenetic studies. This approach can be used to review and support taxonomic revisions and reconstruct evolutionary histories, including historical museum and type specimens.

evolutionary biology↗

bioRxiv2022

Extreme mito-nuclear discordance within Anthozoa, with notes on unique properties of their mitochondrial genomes

Whole mitochondrial genomes are often used in phylogenetic reconstruction. However, discordant patterns in species relationships between mitochondrial and nuclear phylogenies are commonly observed. Within Anthozoa (Phylum Cnidaria), mitochondrial-nuclear discordance has not yet been examined using a large and comparable dataset. Here, we used data obtained from target-capture enrichment sequencing to assemble and annotate mitochondrial genomes and reconstruct phylogenies for comparisons to phylogenies inferred from 100s of nuclear loci obtained from the same samples. The datasets comprised 108 hexacorals and 94 octocorals representing all orders and >50% of extant families. Results indicated rampant discordance between datasets at every taxonomic level. This discordance is not attributable to substitution saturation, but rather likely caused by recent and ancient introgressive hybridization and selection. We also found strong purifying selection across the mitochondrial genomes, cautioning their use in analyses that rely on assumptions of neutrality. Furthermore, unique properties of the mitochondrial genomes were noted, including genome rearrangements and the presence of nad5 introns. Specifically, we note the presence of the homing endonuclease in ceriantharians. This large dataset of mitochondrial genomes further demonstrates the utility of off-target reads generated from target-capture data for mitochondrial genome assembly and adds to the growing knowledge of anthozoan evolution.

evolutionary biology↗

bioRxiv2021

Kilometer-scale larval dispersal processes predict metapopulation connectivity pathways for Paramuricea biscaya in the northern Gulf of Mexico

Fine-scale larval dispersal and connectivity processes are key to species survival, growth, recovery and adaptation under rapidly changing disturbances. Quantifying both are required to develop any effective management strategy. In the present work, we examine the dispersal pattern and potential connectivity of a common deep-water coral, Paramuricea biscaya, found in the northern Gulf of Mexico by evaluating predictions of physical models with estimates of genetic connectivity. While genetic approaches provide estimates of realized connectivity, they do not provide information on the dispersal process. Physical circulation models can now achieve kilometer-scale resolution sufficient to provide detailed insight into the pathways and scales of larval dispersal. A high-resolution regional ocean circulation model is integrated for 2015 and its advective pathways are compared with the outcome of the genetic connectivity estimates of corals collected at six locations over the continental slope at depths comprised between 1000 and 3000 meters. Furthermore, the likely interannual variability is extrapolated using ocean hindcasts available for this basin. The general connectivity pattern exhibits a dispersal trend from east to west following 1000 to 2000-meter isobaths, corresponding to the overall westward near-bottom circulation. The connectivity networks predicted by our model were mostly congruent with the estimated genetic connectivity patterns. Our results show that although dispersal distances of 100 km or less are common, depth differences between tens to a few hundred meters can effectively limit larval dispersal. A probabilistic graphic model suggests that stepping-stone dispersal mediated by intermediate sites provides a likely mechanism for long-distance connectivity between the populations separated by distances of 300 km or greater, such as those found in the DeSoto and Keathley canyons.

ecology↗

bioRxiv2020

New approaches to species delimitation and population structure of corals: two case studies using ultraconserved elements and exons

As coral populations decline worldwide in the face of ongoing environmental change, documenting their distribution, diversity and conservation status is now more imperative than ever. Accurate delimitation and identification of species is a critical first step. This task, however, is not trivial as morphological variation and slowly evolving molecular markers confound species identification. New approaches to species delimitation in corals are needed to overcome these challenges. Here, we test whether target enrichment of ultraconserved elements (UCEs) and exons can be used for delimiting species boundaries and population structure within species of corals by focusing on two octocoral genera, Alcyonium and Sinularia, as exemplary case studies. We designed an updated bait set (29,363 baits) to target-capture 3,040 UCE and exon loci, recovering a mean of 1,910 {+/-} 168 SD per sample with a mean length of 1,055 {+/-} 208 bp. Similar numbers of loci were recovered from Sinularia (1,946 {+/-} 227 SD) and Alcyonium (1,863 {+/-} 177 SD). Species-level phylogenies were highly supported for both genera. Clustering methods based on filtered SNPs delimited species and populations that are congruent with previous allozyme, DNA barcoding, reproductive and ecological data for Alcyonium, and offered further evidence of hybridization among species. For Sinularia, results were congruent with those obtained from a previous study using Restriction Site Associated DNA Sequencing. Both case studies demonstrate the utility of target-enrichment of UCEs and exons to address a wide range of evolutionary and taxonomic questions across deep to shallow time scales in corals.

evolutionary biology↗

bioRxiv2020

An enhanced target-enrichment bait set for Hexacorallia provides phylogenomic resolution of the staghorn corals (Acroporidae) and close relatives.

The phylogenetic utility of targeted enrichment methods has been demonstrated in taxa that often have a history of single gene marker development. These genomic capture methods are now being applied to resolve evolutionary relationships from deep to shallow timescales in clades that were previously deficient in molecular marker development and lacking robust morphological characters that reflect evolutionary relationships. Effectively capturing 1000s of loci, however, in a diverse group across a broad time scale requires a bait set that incorporates multiple baits per locus. We redesigned a custom bait set for the cnidarian class Anthozoa to target 1,436 UCE loci and 1,572 exon regions within the subclass Hexacorallia. We test this redesigned bait set on 99 specimens of hard corals (Scleractinia) spanning both the "complex" (Acroporidae, Agariciidae) and "robust" (Fungiidae) clades. With focused sampling in the staghorn coral genus Acropora we explore the ability of capture data to inform the taxonomy of a clade deficient in molecular resolution. A mean of 1850 ({+/-} 298) loci were captured per taxon (955 UCEs, 894 exons). A 75% complete concatenated alignment included 1792 loci (991 UCE, 801 exons) and [~]1.87 million base pairs. Parsimony informative sites varied from 48% for alignments including all three families, to 1.5% among samples within a single Acropora species. Maximum likelihood and Bayesian analyses recover highly resolved topologies and robust molecular relationships not previously found with traditional markers within the Acroporidae. Species level relationships within the Acropora genus do not support traditional morphological groups or morphological phylogenies. Both UCE and exon datasets delineated six well-supported clades within Acropora. The enhanced bait set for Hexacorallia will allow researchers to survey the evolutionary history of important groups of reef building corals where previous molecular marker development has been unsuccessful.

evolutionary biology↗

bioRxiv2019

A next generation approach to species delimitation reveals the role of hybridization in a cryptic species complex of corals

BackgroundOur ability to investigate processes shaping the evolutionary diversification of corals (Cnidaria: Anthozoa) is limited by a lack of understanding of species boundaries. Discerning species has been challenging due to a multitude of factors, including homoplasious and plastic morphological characters and the use of molecular markers that are either not informative or have not completely sorted. Hybridization can also blur species boundaries by leading to incongruence between morphology and genetics. We used traditional DNA barcoding and restriction-site associated DNA sequencing combined with coalescence-based and allele-frequency methods to elucidate species boundaries and simultaneously examine the potential role of hybridization in a speciose genus of octocoral, Sinularia.\n\nResultsSpecies delimitations using two widely used DNA barcode markers, mtMutS and 28S rDNA, were incongruent with one another and with the morphospecies identifications, likely due to incomplete lineage sorting. In contrast, 12 of the 15 morphospecies examined formed well-supported monophyletic clades in both concatenated RAxML phylogenies and SNAPP species trees of >6,000 RADSeq loci. DAPC and Structure analyses also supported morphospecies assignments, but indicated the potential for two additional cryptic species. Three morphologically distinct species pairs could not, however, be distinguished genetically. ABBA-BABA tests demonstrated significant admixture between some of those species, suggesting that hybridization may confound species delimitation in Sinularia.\n\nConclusionsA genomic approach can help to guide species delimitation while simultaneously elucidating the processes generating diversity in corals. Results support the hypothesis that hybridization is an important mechanism in the evolution of Anthozoa, including octocorals, and future research should examine the contribution of this mechanism in generating diversity across the coral tree of life.

evolutionary biology↗

bioRxiv2018

A Hybrid de novo Assembly of the Sea Pansy (Renilla muelleri) Genome

BackgroundOver 3,000 species of octocorals (Cnidaria, Anthozoa) inhabit an expansive range of environments, from shallow tropical seas to the deep-ocean floor. They are important foundation species that create coral \"forests\" which provide unique niches and three-dimensional living space for other organisms. The octocoral genus Renilla inhabits sandy, continental shelves in the subtropical and tropical Atlantic and eastern Pacific Oceans. Renilla is especially interesting because it produces secondary metabolites for defense, exhibits bioluminescence, and produces a luciferase that is widely used in dual-reporter assays in molecular biology. Although several cnidarian genomes are currently available, the majority are from hexacorals. Here, we present a de novo assembly of the R. muelleri genome, making this the first complete draft genome from an octocoral.\n\nFindingsWe generated a hybrid de novo assembly using the Maryland Super-Read Celera Assembler v.3.2.6 (MaSuRCA). The final assembly included 4,825 scaffolds and a haploid genome size of 172 Mb. A BUSCO assessment found 88% of metazoan orthologs present in the genome. An Augustus ab initio gene prediction found 23,660 genes, of which 66% (15,635) had detectable similarity to annotated genes from the starlet sea anemone, Nematostella vectensis, or to the Uniprot database. Although the R. muelleri genome is smaller (172 Mb) than other publicly available, hexacoral genomes (256-448 Mb), the R. muelleri genome is similar to the hexacoral genomes in terms of the number of complete metazoan BUSCOs and predicted gene models.\n\nConclusionsThe R. muelleri hybrid genome provides a novel resource for researchers to investigate the evolution of genes and gene families within Octocorallia and more widely across Anthozoa. It will be a key resource for future comparative genomics with other corals and for understanding the genomic basis of coral diversity.

genomics↗