| 1. |
- Tittensor, Derek P., et al.
(author)
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A protocol for the intercomparison of marine fishery and ecosystem models : Fish-MIP v1.0
- 2018
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In: Geoscientific Model Development. - : Copernicus GmbH. - 1991-959X .- 1991-9603. ; 11:4, s. 1421-1442
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Journal article (peer-reviewed)abstract
- Model intercomparison studies in the climate and Earth sciences communities have been crucial to building credibility and coherence for future projections. They have quantified variability among models, spurred model development, contrasted within- and among-model uncertainty, assessed model fits to historical data, and provided ensemble projections of future change under specified scenarios. Given the speed and magnitude of anthropogenic change in the marine environment and the consequent effects on food security, biodiversity, marine industries, and society, the time is ripe for similar comparisons among models of fisheries and marine ecosystems. Here, we describe the Fisheries and Marine Ecosystem Model Intercomparison Project protocol version 1.0 (Fish-MIP v1.0), part of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), which is a cross-sectoral network of climate impact modellers. Given the complexity of the marine ecosystem, this class of models has substantial heterogeneity of purpose, scope, theoretical underpinning, processes considered, parameterizations, resolution (grain size), and spatial extent. This heterogeneity reflects the lack of a unified understanding of the marine ecosystem and implies that the assemblage of all models is more likely to include a greater number of relevant processes than any single model. The current Fish-MIP protocol is designed to allow these heterogeneous models to be forced with common Earth System Model (ESM) Coupled Model Intercomparison Project Phase 5 (CMIP5) outputs under prescribed scenarios for historic (from the 1950s) and future (to 2100) time periods; it will be adapted to CMIP phase 6 (CMIP6) in future iterations. It also describes a standardized set of outputs for each participating Fish-MIP model to produce. This enables the broad characterization of differences between and uncertainties within models and projections when assessing climate and fisheries impacts on marine ecosystems and the services they provide. The systematic generation, collation, and comparison of results from Fish-MIP will inform an understanding of the range of plausible changes in marine ecosystems and improve our capacity to define and convey the strengths and weaknesses of model-based advice on future states of marine ecosystems and fisheries. Ultimately, Fish-MIP represents a step towards bringing together the marine ecosystem modelling community to produce consistent ensemble medium- and long-term projections of marine ecosystems.
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| 2. |
- Galbraith, James D., et al.
(author)
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Genome Stability Is in the Eye of the Beholder : CR1 Retrotransposon Activity Varies Significantly across Avian Diversity
- 2021
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In: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653. ; 13:12
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Journal article (peer-reviewed)abstract
- Since the sequencing of the zebra finch genome it has become clear that avian genomes, while largely stable in terms of chromosome number and gene synteny, are more dynamic at an intrachromosomal level. A multitude of intrachromosomal rearrangements and significant variation in transposable element (TE) content have been noted across the avian tree. TEs are a source of genome plasticity, because their high similarity enables chromosomal rearrangements through nonallelic homologous recombination, and they have potential for exaptation as regulatory and coding sequences. Previous studies have investigated the activity of the dominant TE in birds, chicken repeat 1 (CR1) retrotransposons, either focusing on their expansion within single orders, or comparing passerines with nonpasserines. Here, we comprehensively investigate and compare the activity of CR1 expansion across orders of birds, finding levels of CR1 activity vary significantly both between and within orders. We describe high levels of TE expansion in genera which have speciated in the last 10 Myr including kiwis, geese, and Amazon parrots; low levels of TE expansion in songbirds across their diversification, and near inactivity of TEs in the cassowary and emu for millions of years. CR1s have remained active over long periods of time across most orders of neognaths, with activity at any one time dominated by one or two families of CR1 s. Our findings of higher TE activity in species -rich clades and dominant families of TEs within lineages mirror past findings in mammals and indicate that genome evolution in amniotes relies on universal TE-driven processes.
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| 3. |
- Galbraith, James D., et al.
(author)
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Horizontal transfer and subsequent explosive expansion of a DNA transposon in sea kraits (Laticauda)
- 2021
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In: Biology Letters. - : Royal Society. - 1744-9561 .- 1744-957X. ; 17:9
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Journal article (peer-reviewed)abstract
- Transposable elements (TEs) are self-replicating genetic sequences and are often described as important 'drivers of evolution'. This driving force is because TEs promote genomic novelty by enabling rearrangement, and through exaptation as coding and regulatory elements. However, most TE insertions potentially lead to neutral or harmful outcomes, therefore host genomes have evolved machinery to suppress TE expansion. Through horizontal transposon transfer (HTT) TEs can colonize new genomes, and since new hosts may not be able to regulate subsequent replication, these TEs may proliferate rapidly. Here, we describe HTT of the Harbinger-Snek DNA transposon into sea kraits (Laticauda), and its subsequent explosive expansion within Laticauda genomes. This HTT occurred following the divergence of Laticauda from terrestrial Australian elapids approximately 15-25 Mya. This has resulted in numerous insertions into introns and regulatory regions, with some insertions into exons which appear to have altered UTRs or added sequence to coding exons. Harbinger-Snek has rapidly expanded to make up 8-12% of Laticauda spp. genomes; this is the fastest known expansion of TEs in amniotes following HTT. Genomic changes caused by this rapid expansion may have contributed to adaptation to the amphibious-marine habitat.
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| 4. |
- Galbraith, James D., et al.
(author)
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Horizontal Transposon Transfer and Its Implications for the Ancestral Ecology of Hydrophiine Snakes
- 2022
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In: Genes. - : MDPI. - 2073-4425. ; 13:2
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Journal article (peer-reviewed)abstract
- Transposable elements (TEs), also known as jumping genes, are sequences able to move or copy themselves within a genome. As TEs move throughout genomes they often act as a source of genetic novelty, hence understanding TE evolution within lineages may help in understanding environmental adaptation. Studies into the TE content of lineages of mammals such as bats have uncovered horizontal transposon transfer (HTT) into these lineages, with squamates often also containing the same TEs. Despite the repeated finding of HTT into squamates, little comparative research has examined the evolution of TEs within squamates. Here we examine a diverse family of Australo-Melanesian snakes (Hydrophiinae) to examine if the previously identified, order-wide pattern of variable TE content and activity holds true on a smaller scale. Hydrophiinae diverged from Asian elapids similar to 30 Mya and have since rapidly diversified into six amphibious, similar to 60 marine and similar to 100 terrestrial species that fill a broad range of ecological niches. We find TE diversity and expansion differs between hydrophiines and their Asian relatives and identify multiple HTTs into Hydrophiinae, including three likely transferred into the ancestral hydrophiine from fish. These HTT events provide the first tangible evidence that Hydrophiinae reached Australia from Asia via a marine route.
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| 5. |
- Galbraith, James D., et al.
(author)
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New Environment, New Invaders-Repeated Horizontal Transfer of LINEs to Sea Snakes
- 2020
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In: Genome Biology and Evolution. - : OXFORD UNIV PRESS. - 1759-6653. ; 12:12, s. 2370-2383
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Journal article (peer-reviewed)abstract
- Although numerous studies have found horizontal transposon transfer (HTT) to be widespread across metazoans, few have focused on HTT in marine ecosystems. To investigate potential recent HTTs into marine species, we searched for novel repetitive elements in sea snakes, a group of elapids which transitioned to a marine habitat at most 18 Ma. Our analysis uncovered repeated HTTs into sea snakes following their marine transition. The seven subfamilies of horizontally transferred LINE retrotransposons we identified in the olive sea snake (Aipysurus laevis) are transcribed, and hence are likely still active and expanding across the genome. A search of 600 metazoan genomes found all seven were absent from other amniotes, including terrestrial elapids, with the most similar LINEs present in fish and marine invertebrates. The one exception was a similar LINE found in sea kraits, a lineage of amphibious elapids which independently transitioned to a marine environment 25 Ma. Our finding of repeated horizontal transfer events into marine snakes greatly expands past findings that the marine environment promotes the transfer of transposons. Transposons are drivers of evolution as sources of genomic sequence and hence genomic novelty. We identified 13 candidate genes for HTT-induced adaptive change based on internal or neighboring HTT LINE insertions. One of these, ADCY4, is of particular interest as a part of the KEGG adaptation pathway "Circadian Entrainment." This provides evidence of the ecological interactions between species influencing evolution of metazoans not only through specific selection pressures, but also by contributing novel genomic material.
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