The Amazonian marsh rat, Holochilus sciureus, is a member of the subfamily Sigmodontinae, the second-largest subfamily of muroid rodents, with 410 species and ca. 84 genera in 12 tribes. This semiaquatic rodent is distributed in South America and is of great economic and epidemiological importance. In this study, we obtained the first mitochondrial genome of the genus Holochilus obtained from a tissue sample associated with a museum voucher specimen. The generated mitogenome sequence of H. sciureus is 16,358 bp length. It comprises a control region and a conserved set of 37 genes encoding for 2 rRNA genes, 22 tRNA genes and 13 protein-coding genes. We conducted a phylogenetic analysis that included H. sciureus and the only five other published mitochondrial genomes of this poorly studied subfamily of rodents.
Full plastome sequences for land plants have become readily accessible thanks to the development of Next Generation Sequencing (NGS) techniques and powerful bioinformatic tools. Despite this vast amount of genomic data, some lineages remain understudied. Full plastome sequences from the highly diverse (>1,500 spp.) subfamily Tillandsioideae (Bromeliaceae, Poales) have been published for only three (i.e., Guzmania , Tillandsia , and Vriesea ) out of 22 currently recognized genera. Here, we focus on core Tillandsioideae, a clade within subfamily Tillandsioideae, and explore the contribution of individual plastid markers and data categories to inform deep divergences of a plastome phylogeny. We generated 37 high quality plastome assemblies and performed a comparative analysis in terms of plastome structure, size, gene content and order, GC content, as well as number and type of repeat motifs. Using the obtained phylogenetic context, we reconstructed the evolution of these plastome attributes and assessed if significant shifts on the evolutionary traits’ rates have occurred in the evolution of the core Tillandsioideae. Our results agree with previously published phylogenetic hypotheses based on plastid data, providing stronger statistical support for some recalcitrant nodes. However, phylogenetic discordance with previously published nuclear marker-based hypotheses was found. Several plastid markers that have been consistently used to address phylogenetic relationships within Tillandsioideae were highly informative for the retrieved plastome phylogeny and further loci are here identified as promising additional markers for future studies. New lineage-specific plastome rearrangements were found to support recently adopted taxonomic groups, including large inversions, as well as expansions and contractions of the inverted repeats. Evolutionary trait rate shifts associated with changes in size and GC content of the plastome regions were found across the phylogeny of core Tillandsioideae.
In the framework of neutral theory of molecular evolution, genes specific to the development and function of eyes in subterranean animals living in permanent darkness are expected to evolve by relaxed selection, ultimately becoming pseudogenes. However, definitive empirical evidence for the role of neutral processes in the loss of vision over evolutionary time remains controversial. In previous studies, we characterized an assemblage of independently-evolved water beetle (Dytiscidae) species from a subterranean archipelago in Western Australia, where parallel vision and eye loss have occurred. Using a combination of transcriptomics and exon capture, we present evidence of parallel coding sequence decay, resulting from the accumulation of frameshift mutations and premature stop codons, in eight phototransduction genes (arrestins, opsins, ninaC and transient receptor potential channel genes) in 32 subterranean species in contrast to surface species, where these genes have open reading frames. Our results provide strong evidence to support neutral evolutionary processes as a major contributing factor to the loss of phototransduction genes in subterranean animals, with the ultimate fate being the irreversible loss of a light detection system.
Although recent molecular phylogenetic analyses of Lepidothrix manakins (family Pipridae) have helped clarify their evolutionary relationships, the placement of several lineages remains in question because of low or conflicting branch support. In particular, the relationship of L. coronata to other members of the genus and relationships within the L. nattereri + L. vilasboasi + L. iris clade have been difficult to resolve. We used RADcap to collect restriction site-associated DNA sequence data and estimate the first subspecies-level phylogeny of the genus Lepidothrix (17 of 18 currently recognized subspecies), and we included extensive geographic representation of the widespread and phenotypically variable L. coronata. We found strong support for the phylogenetic position and monophyly of L. coronata, and we resolved two clades separated by the Andes that, along with previous divergence time estimates and our assessment of morphological and vocal evidence, suggest the presence of two biological species: Velvety Manakin (L. velutina) west of the Andes and Blue-capped Manakin (L. coronata) east of the Andes. Species-level relationships within the L. nattereri + L. vilasboasi + L. iris clade remained poorly resolved in concatenated and coalescent-based analyses, with SNAPP analyses suggesting that the lack of reciprocal monophyly is due to extensive allele sharing among these taxa. Finally, we confirmed a previously documented hybrid between L. coronata and L. suavissima as an F1 individual, consistent with the view that hybridization between these two species is a rare event and that postmating reproductive barriers prevent successful backcrossing.
Human herpes simplex virus 1 (HSV-1), a life-long infection spread by oral contact, infects a majority of adults globally. Phylogeographic clustering of sampled diversity into European, pan-Eurasian, and African groups has suggested the virus codiverged with human migrations out of Africa, although a much younger origin has also been proposed. We present three full ancient European HSV-1 genomes and one partial genome, dating from the 3rd to 17th century CE, sequenced to up to 9.5× with paired human genomes up to 10.16×. Considering a dataset of modern and ancient genomes, we apply phylogenetic methods to estimate the age of sampled modern Eurasian HSV-1 diversity to 4.68 (3.87 to 5.65) ka. Extrapolation of estimated rates to a global dataset points to the age of extant sampled HSV-1 as 5.29 (4.60 to 6.12) ka, suggesting HSV-1 lineage replacement coinciding with the late Neolithic period and following Bronze Age migrations. , Medieval human herpes simplex virus 1 genomes implicate Bronze Age migrations in lineage distribution in Eurasia.
Pandemics originating from non-human animals highlight the need to understand how natural hosts have evolved in response to emerging human pathogens and which groups may be susceptible to infection and/or potential reservoirs to mitigate public health and conservation concerns. Multiple zoonotic coronaviruses, such as severe acute respiratory syndrome-associated coronavirus (SARS-CoV), SARS-CoV-2 and Middle Eastern respiratory syndrome-associated coronavirus (MERS-CoV), are hypothesized to have evolved in bats. We investigate angiotensin-converting enzyme 2 (ACE2), the host protein bound by SARS-CoV and SARS-CoV-2, and dipeptidyl-peptidase 4 (DPP4 or CD26), the host protein bound by MERS-CoV, in the largest bat datasets to date. Both the ACE2 and DPP4 genes are under strong selection pressure in bats, more so than in other mammals, and in residues that contact viruses. Additionally, mammalian groups vary in their similarity to humans in residues that contact SARS-CoV, SARS-CoV-2 and MERS-CoV, and increased similarity to humans in binding residues is broadly predictive of susceptibility to SARS-CoV-2. This work augments our understanding of the relationship between coronaviruses and mammals, particularly bats, provides taxonomically diverse data for studies of how host proteins are bound by coronaviruses and can inform surveillance, conservation and public health efforts.
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