| 1. |
- Bentley, Blair P., et al.
(författare)
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Divergent sensory and immune gene evolution in sea turtles with contrasting demographic and life histories
- 2023
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 120:7
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Tidskriftsartikel (refereegranskat)abstract
- Sea turtles represent an ancient lineage of marine vertebrates that evolved from terrestrial ancestors over 100 Mya. The genomic basis of the unique physiological and ecological traits enabling these species to thrive in diverse marine habitats remains largely unknown. Additionally, many populations have drastically declined due to anthropogenic activities over the past two centuries, and their recovery is a high global conservation priority. We generated and analyzed high-quality reference genomes for the leatherback (Dermochelys coriacea) and green (Chelonia mydas) turtles, representing the two extant sea turtle families. These genomes are highly syntenic and homologous, but localized regions of noncollinearity were associated with higher copy numbers of immune, zinc-finger, and olfactory receptor (OR) genes in green turtles, with ORs related to waterborne odorants greatly expanded in green turtles. Our findings suggest that divergent evolution of these key gene families may underlie immunological and sensory adaptations assisting navigation, occupancy of neritic versus pelagic environments, and diet specialization. Reduced collinearity was especially prevalent in microchromosomes, with greater gene content, heterozygosity, and genetic distances between species, supporting their critical role in vertebrate evolutionary adaptation. Finally, diversity and demographic histories starkly contrasted between species, indicating that leatherback turtles have had a low yet stable effective population size, exhibit extremely low diversity compared with other reptiles, and harbor a higher genetic load compared with green turtles, reinforcing concern over their persistence under future climate scenarios. These genomes provide invaluable resources for advancing our understanding of evolution and conservation best practices in an imperiled vertebrate lineage.
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| 2. |
- Dahn, Hollis A., et al.
(författare)
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Benchmarking ultra-high molecular weight DNA preservation methods for long-read and long-range sequencing
- 2022
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Ingår i: GigaScience. - : Oxford University Press. - 2047-217X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies in vertebrate genomics require sampling from a broad range of tissue types, taxa, and localities. Recent advancements in long-read and long-range genome sequencing have made it possible to produce high-quality chromosome-level genome assemblies for almost any organism. However, adequate tissue preservation for the requisite ultra-high molecular weight DNA (uHMW DNA) remains a major challenge. Here we present a comparative study of preservation methods for field and laboratory tissue sampling, across vertebrate classes and different tissue types.Results: We find that storage temperature was the strongest predictor of uHMW fragment lengths. While immediate flash-freezing remains the sample preservation gold standard, samples preserved in 95% EtOH or 20-25% DMSO-EDTA showed little fragment length degradation when stored at 4 degrees C for 6 hours. Samples in 95% EtOH or 20-25% DMSO-EDTA kept at 4 degrees C for 1 week after dissection still yielded adequate amounts of uHMW DNA for most applications. Tissue type was a significant predictor of total DNA yield but not fragment length. Preservation solution had a smaller but significant influence on both fragment length and DNA yield.Conclusion: We provide sample preservation guidelines that ensure sufficient DNA integrity and amount required for use with long-read and long-range sequencing technologies across vertebrates. Our best practices generated the uHMW DNA needed for the high-quality reference genomes for phase 1 of the Vertebrate Genomes Project, whose ultimate mission is to generate chromosome-level reference genome assemblies of all similar to 70,000 extant vertebrate species.
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| 3. |
- Dussex, Nicolas, et al.
(författare)
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Population genomics of the critically endangered kākāpō
- 2021
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Ingår i: Cell Genomics. - : Elsevier BV. - 2666-979X. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- Summary The kākāpō is a flightless parrot endemic to New Zealand. Once common in the archipelago, only 201 individuals remain today, most of them descending from an isolated island population. We report the first genome-wide analyses of the species, including a high-quality genome assembly for kākāpō, one of the first chromosome-level reference genomes sequenced by the Vertebrate Genomes Project (VGP). We also sequenced and analyzed 35 modern genomes from the sole surviving island population and 14 genomes from the extinct mainland population. While theory suggests that such a small population is likely to have accumulated deleterious mutations through genetic drift, our analyses on the impact of the long-term small population size in kākāpō indicate that present-day island kākāpō have a reduced number of harmful mutations compared to mainland individuals. We hypothesize that this reduced mutational load is due to the island population having been subjected to a combination of genetic drift and purging of deleterious mutations, through increased inbreeding and purifying selection, since its isolation from the mainland ∼10,000 years ago. Our results provide evidence that small populations can survive even when isolated for hundreds of generations. This work provides key insights into kākāpō breeding and recovery and more generally into the application of genetic tools in conservation efforts for endangered species.
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| 4. |
- Formenti, Giulio, et al.
(författare)
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The era of reference genomes in conservation genomics
- 2022
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Ingår i: Trends in Ecology & Evolution. - : Elsevier. - 0169-5347 .- 1872-8383. ; 37:3, s. 197-202
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Progress in genome sequencing now enables the large-scale generation of reference genomes. Various international initiatives aim to generate reference genomes representing global biodiversity. These genomes provide unique insights into genomic diversity and architecture, thereby enabling comprehensive analyses of population and functional genomics, and are expected to revolutionize conservation genomics.
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| 5. |
- Karawita, Anjana C., et al.
(författare)
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The swan genome and transcriptome, it is not all black and white
- 2023
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Ingår i: Genome Biology. - : BioMed Central (BMC). - 1465-6906 .- 1474-760X. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe Australian black swan (Cygnus atratus) is an iconic species with contrasting plumage to that of the closely related northern hemisphere white swans. The relative geographic isolation of the black swan may have resulted in a limited immune repertoire and increased susceptibility to infectious diseases, notably infectious diseases from which Australia has been largely shielded. Unlike mallard ducks and the mute swan (Cygnus olor), the black swan is extremely sensitive to highly pathogenic avian influenza. Understanding this susceptibility has been impaired by the absence of any available swan genome and transcriptome information.ResultsHere, we generate the first chromosome-length black and mute swan genomes annotated with transcriptome data, all using long-read based pipelines generated for vertebrate species. We use these genomes and transcriptomes to show that unlike other wild waterfowl, black swans lack an expanded immune gene repertoire, lack a key viral pattern-recognition receptor in endothelial cells and mount a poorly controlled inflammatory response to highly pathogenic avian influenza. We also implicate genetic differences in SLC45A2 gene in the iconic plumage of the black swan.ConclusionTogether, these data suggest that the immune system of the black swan is such that should any avian viral infection become established in its native habitat, the black swan would be in a significant peril.
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| 6. |
- Lewin, Harris A., et al.
(författare)
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The Earth BioGenome Project 2020 : Starting the clock
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 119:4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Squires, Theodore E., et al.
(författare)
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A chromosome-level genome assembly for the Rock Ptarmigan (Lagopus muta)
- 2023
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Ingår i: G3. - : Oxford University Press. - 2160-1836. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- The Rock Ptarmigan (Lagopus muta) is a cold-adapted, largely sedentary, game bird with a Holarctic distribution. The species represents an important example of an organism likely to be affected by ongoing climatic shifts across a disparate range. We provide here a highquality reference genome and mitogenome for the Rock Ptarmigan assembled from PacBio HiFi and Hi-C sequencing of a female bird from Iceland. The total size of the genome is 1.03 Gb with a scaffold N50 of 71.23 Mb and a contig N50 of 17.91 Mb. The final scaffolds represent all 40 predicted chromosomes, and the mitochondria with a BUSCO score of 98.6%. Gene annotation resulted in 16,078 protein-coding genes out of a total 19,831 predicted (81.08% excluding pseudogenes). The genome included 21.07% repeat sequences, and the average length of genes, exons, and introns were 33605, 394, and 4265 bp, respectively. The availability of a new reference-quality genome will contribute to understanding the Rock Ptarmigan's unique evolutionary history, vulnerability to climate change, and demographic trajectories around the globe while serving as a benchmark for species in the family Phasianidae (order Galliformes).
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| 8. |
- Theissinger, Kathrin, et al.
(författare)
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How genomics can help biodiversity conservation
- 2023
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Ingår i: Trends in Genetics. - : Elsevier. - 0168-9525 .- 1362-4555. ; 39:7, s. 545-559
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Forskningsöversikt (refereegranskat)abstract
- The availability of public genomic resources can greatly assist biodiversity assessment, conservation, and restoration efforts by providing evidence for scientifically informed management decisions. Here we survey the main approaches and applications in biodiversity and conservation genomics, considering practical factors, such as cost, time, prerequisite skills, and current shortcomings of applications. Most approaches perform best in combination with reference genomes from the target species or closely related species. We review case studies to illustrate how reference genomes can facilitate biodiversity research and conservation across the tree of life. We conclude that the time is ripe to view reference genomes as fundamental resources and to integrate their use as a best practice in conservation genomics.
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