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Carruthers, T.

Publications and source records attributed to Carruthers, T..

4 recordsLinked to original sources

A large phylogenetic tree for euphyllophytes

PremiseMolecular datasets for estimating phylogenetic trees increasingly include more species and gene regions. Often trees are constructed using backbone phylogenies, subtrees, and other techniques to address the challenges of large dataset size. Currently, there is no established approach to integrate these rapidly expanding datasets. MethodsWe generated a phylogenetic tree (and 1,000 bootstrap trees) with divergence times that span euphyllophytes. To do this, we integrated taxonomically broad dated backbone phylogenies with species-level trees generated from phylogenetic analysis of individual clades. Datasets for species-level trees were assembled using PyPHLAWD. ResultsThe resulting dated phylogenetic tree includes: 121,641 angiosperm species; 1,026 gymnosperms; and 5,603 ferns. This is the largest euphyllophyte phylogenetic tree constructed to date. Topological uncertainty spikes at the start of the Cretaceous and gradually increases during the Cenozoic. Uncertainty in age estimates gradually increases in the Cenozoic but increases dramatically in the most recent 5 Myrs. DiscussionThis dated phylogenetic framework can underpin evolutionary studies spanning euphyllophytes, and enable the integration of insights from the recent to the distant past. Our approach also enables the tree to be easily updated in the future to reflect future increases in data availability, and systematic and taxonomic advances within specific clades.

plant biology↗

Longevity in plants impacts phylogenetic and population dynamics

Many long-lived plant species exhibit notable patterns in phylogenies, such as short molecular branch lengths and high gene-tree conflict. However, it is not clear what biological properties of long-lived plant species or concomitant processes acting within these lineages generate these patterns. To explore this mystery, we implemented an agent-based model and conducted simulations to investigate how longevity affects molecular evolution and population dynamics. Through these simulations, we demonstrated that the patterns exhibited in empirical datasets for long-lived species can be explained by their lifespan and overlapping generations. We also show that somatic mutations can exacerbate these patterns, although evidence for substantive rates in empirical systems high enough to impact phylogenetic patterns is scarce. We discuss several empirical datasets containing life history shifts that exhibit diverse phylogenomic patterns. The variation produced through different parameterizations of our simulations reflects the diversity of patterns found in empirical datasets. Our results have broad implications for phylogenomic patterns and population genetics in general, as well as for specifically explaining patterns of evolution in long-lived lineages.

evolutionary biology↗

A Comprehensive Phylogenomic Platform for Exploring the Angiosperm Tree of Life

The tree of life is the fundamental biological roadmap for navigating the evolution and properties of life on Earth, and yet remains largely unknown. Even angiosperms (flowering plants) are fraught with data gaps, despite their critical role in sustaining terrestrial life. Today, high-throughput sequencing promises to significantly deepen our understanding of evolutionary relationships. Here, we describe a comprehensive phylogenomic platform for exploring the angiosperm tree of life, comprising a set of open tools and data based on the 353 nuclear genes targeted by the universal Angiosperms353 sequence capture probes. This paper (i) documents our methods, (ii) describes our first data release and (iii) presents a novel open data portal, the Kew Tree of Life Explorer (https://treeoflife.kew.org). We aim to generate novel target sequence capture data for all genera of flowering plants, exploiting natural history collections such as herbarium specimens, and augment it with mined public data. Our first data release, described here, is the most extensive nuclear phylogenomic dataset for angiosperms to date, comprising 3,099 samples validated by DNA barcode and phylogenetic tests, representing all 64 orders, 404 families (96%) and 2,333 genera (17%). Using the multi-species coalescent, we inferred a "first pass" angiosperm tree of life from the data, which totalled 824,878 sequences, 489,086,049 base pairs, and 532,260 alignment columns. The tree is strongly supported and highly congruent with existing taxonomy, while challenging numerous hypothesized relationships among orders and placing many genera for the first time. The validated dataset, species tree and all intermediates are openly accessible via the Kew Tree of Life Explorer. This major milestone towards a complete tree of life for all flowering plant species opens doors to a highly integrated future for angiosperm phylogenomics through the systematic sequencing of standardised nuclear markers. Our approach has the potential to serve as a much-needed bridge between the growing movement to sequence the genomes of all life on Earth and the vast phylogenomic potential of the worlds natural history collections.

evolutionary biology↗

Temporal Dynamics of the Origin and Domestication of Sweet Potato and Implications for Dispersal to Polynesia

In a study focussed on the origin of Ipomoea batatas (L.) Lam. (the sweet potato) and its close relatives [1], the authors claimed that a specimen of sweet potato collected by Banks and Solander in 1769 in Polynesia was distinct and along with some other varieties had levels of genetic variation of more than 100,000 years. This timeframe, along with several other lines of evidence, was interpreted, by the authors, as questioning human-mediated transport of the sweet potato to Polynesia within the last 1,000 years. This aspect of the paper received widespread media coverage as well as a number of critical remarks, and correspondence. The criticism questioned whether claims in the paper were justified. Here, three authors from the paper take the opportunity to fully explain the reasoning for calling into question the need to invoke human mediated transport of the sweet potato to Polynesia.

plant biology↗