ORCID Profile
0000-0002-6229-3596
Current Organisation
Carnegie Institution for Science
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Publisher: Springer Science and Business Media LLC
Date: 21-05-0002
DOI: 10.1186/S40645-020-00327-1
Abstract: Mantle tomography reveals the existence of two large low-shear-velocity provinces (LLSVPs) at the base of the mantle. We examine here the hypothesis that they are piles of oceanic crust that have steadily accumulated and warmed over billions of years. We use existing global geodynamic models in which dense oceanic crust forms at ergent plate boundaries and subducts at convergent ones. The model suite covers the predicted density range for oceanic crust over lower mantle conditions. To meaningfully compare our geodynamic models to tomographic structures, we convert them into models of seismic wavespeed and explicitly account for the limited resolving power of tomography. Our results demonstrate that long-term recycling of dense oceanic crust naturally leads to the formation of thermochemical piles with seismic characteristics similar to the LLSVPs. The extent to which oceanic crust contributes to the LLSVPs depends upon its density in the lower mantle for which accurate data is lacking. We find that the LLSVPs are not composed solely of oceanic crust. Rather, they are basalt rich at their base (bottom 100–200 km) and grade into peridotite toward their sides and top with the strength of their seismic signature arising from the dominant role of temperature. We conclude that recycling of oceanic crust, if sufficiently dense, has a strong influence on the thermal and chemical evolution of Earth’s mantle.
Publisher: American Geophysical Union (AGU)
Date: 03-2021
DOI: 10.1029/2020GC009396
Publisher: Cold Spring Harbor Laboratory
Date: 08-12-2019
DOI: 10.1101/867069
Abstract: The tuatara ( Sphenodon punctatus ), the only living member of the archaic reptilian order Rhynchocephalia (Sphenodontia) once widespread across Gondwana, is an iconic and enigmatic terrestrial vertebrate endemic to New Zealand. A key link to the now extinct stem reptiles from which dinosaurs, modern reptiles, birds and mammals evolved, the tuatara provides exclusive insights into the ancestral amniotes. The tuatara genome, at ∼5 Gbp, is among the largest vertebrate genomes assembled. Analysis of this genome and comparisons to other vertebrates reinforces the uniqueness of the tuatara. Phylogenetic analyses indicate tuatara erged from the snakes and lizards ∼250 MYA. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Genome sequence analysis identifies expansions of protein, non-protein-coding RNA families, and repeat elements, the latter of which show an extraordinary amalgam of reptilian and mammalian features. Sequencing of this genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. It also provides important insights into both the technical challenges and the cultural obligations associated with genome sequencing.
Publisher: Oxford University Press (OUP)
Date: 24-02-2021
Abstract: During the Miocene, Hyaenidae was a highly erse family of Carnivora that has since been severely reduced to four species: the bone-cracking spotted, striped, and brown hyenas, and the specialized insectivorous aardwolf. Previous studies investigated the evolutionary histories of the spotted and brown hyenas, but little is known about the remaining two species. Moreover, the genomic underpinnings of scavenging and insectivory, defining traits of the extant species, remain elusive. Here, we generated an aardwolf genome and analyzed it together with the remaining three species to reveal their evolutionary relationships, genomic underpinnings of their scavenging and insectivorous lifestyles, and their respective genetic ersities and demographic histories. High levels of phylogenetic discordance suggest gene flow between the aardwolf lineage and the ancestral brown/striped hyena lineage. Genes related to immunity and digestion in the bone-cracking hyenas and craniofacial development in the aardwolf showed the strongest signals of selection, suggesting putative key adaptations to carrion and termite feeding, respectively. A family-wide expansion in olfactory receptor genes suggests that an acute sense of smell was a key early adaptation. Finally, we report very low levels of genetic ersity within the brown and striped hyenas despite no signs of inbreeding, putatively linked to their similarly slow decline in effective population size over the last ∼2 million years. High levels of genetic ersity and more stable population sizes through time are seen in the spotted hyena and aardwolf. Taken together, our findings highlight how ecological specialization can impact the evolutionary history, demographics, and adaptive genetic changes of an evolutionary lineage.
Publisher: Springer Science and Business Media LLC
Date: 18-08-2020
DOI: 10.1038/S41586-020-2661-6
Abstract: An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Publisher: Elsevier BV
Date: 10-2020
Publisher: Springer Science and Business Media LLC
Date: 26-04-2021
DOI: 10.1038/S41467-021-22386-8
Abstract: Small populations are often exposed to high inbreeding and mutational load that can increase the risk of extinction. The Sumatran rhinoceros was widespread in Southeast Asia, but is now restricted to small and isolated populations on Sumatra and Borneo, and most likely extinct on the Malay Peninsula. Here, we analyse 5 historical and 16 modern genomes from these populations to investigate the genomic consequences of the recent decline, such as increased inbreeding and mutational load. We find that the Malay Peninsula population experienced increased inbreeding shortly before extirpation, which possibly was accompanied by purging. The populations on Sumatra and Borneo instead show low inbreeding, but high mutational load. The currently small population sizes may thus in the near future lead to inbreeding depression. Moreover, we find little evidence for differences in local adaptation among populations, suggesting that future inbreeding depression could potentially be mitigated by assisted gene flow among populations.
Publisher: Springer Science and Business Media LLC
Date: 05-08-2020
DOI: 10.1038/S41586-020-2561-9
Abstract: The tuatara ( Sphenodon punctatus )—the only living member of the reptilian order Rhynchocephalia (Sphenodontia), once widespread across Gondwana 1,2 —is an iconic species that is endemic to New Zealand 2,3 . A key link to the now-extinct stem reptiles (from which dinosaurs, modern reptiles, birds and mammals evolved), the tuatara provides key insights into the ancestral amniotes 2,4 . Here we analyse the genome of the tuatara, which—at approximately 5 Gb—is among the largest of the vertebrate genomes yet assembled. Our analyses of this genome, along with comparisons with other vertebrate genomes, reinforce the uniqueness of the tuatara. Phylogenetic analyses indicate that the tuatara lineage erged from that of snakes and lizards around 250 million years ago. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Our genome sequence analysis identifies expansions of proteins, non-protein-coding RNA families and repeat elements, the latter of which show an amalgam of reptilian and mammalian features. The sequencing of the tuatara genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. Our study also provides important insights into both the technical challenges and the cultural obligations that are associated with genome sequencing.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 10-07-2020
Abstract: A decentralized model could address global health risks associated with wildlife exploitation
Publisher: American Geophysical Union (AGU)
Date: 10-2010
DOI: 10.1029/2010GC003050
Publisher: Oxford University Press (OUP)
Date: 27-11-2019
DOI: 10.1093/GBE/EVZ264
Abstract: Members of the speciose insect order Trichoptera (caddisflies) provide important ecosystem services, for ex le, nutrient cycling through breaking down of organic matter. They are also of industrial interest due to their larval silk secretions. These form the basis for their erse case-making behavior that allows them to exploit a wide range of ecological niches. Only five genomes of this order have been published thus far, with variable qualities regarding contiguity and completeness. A low-cost sequencing strategy, that is, using a single Oxford Nanopore flow cell per in idual along with Illumina sequence reads was successfully used to generate high-quality genomes of two Trichoptera species, Plectrocnemia conspersa and Hydropsyche tenuis. Of the de novo assembly methods compared, assembly of low coverage Nanopore reads (∼18×) and subsequent polishing with long reads followed by Illumina short reads (∼80–170× coverage) yielded the highest genome quality both in terms of contiguity and BUSCO completeness. The presented genomes are the shortest to date and extend our knowledge of genome size across caddisfly families. The genomic region that encodes for light (L)-chain fibroin, a protein component of larval caddisfly silk was identified and compared with existing L-fibroin gene clusters. The new genomic resources presented in this paper are among the highest quality Trichoptera genomes and will increase the knowledge of this important insect order by serving as the basis for phylogenomic and comparative genomic studies.
Publisher: Wiley
Date: 27-08-2020
No related grants have been discovered for Stefan Prost.