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Most efforts at improving accuracy in phylogenomic reconstructions have focused on improving tree‐building methods or orthology determination. Even though the use of whole genome sequence or transcriptome data is increasing, the degree to which accurate genome assembly and annotation influence phylogenetic inference has not been well explored. Here, we use low‐coverage whole genome sequencing of spionid annelids to explore the impact of different assemblers and annotation strategies on tree reconstruction. We also produce a phylogenetic hypothesis that spans the breadth of Spionidae, examining the current systematics of the group, which is based on morphological parsimony analyses and classical taxonomy. Our results show that both assembly and annotation can have important consequences for the pool of loci that may be available for tree reconstruction. When an identical phylogenomic pipeline is used, differences in assembly and annotation can account for variation in reconstructed topologies. Interestingly, the completeness and depth of the data used for training annotation software (i.e. data from model systems) appear to be more important, by some measures, than the degree of phylogenetic relatedness of the organism from which training data are drawn. Despite variation in recovered topologies, the recognised subfamily Spioninae is nested within Nerininae, suggesting that diagnostic characters of Nerininae (e.g. thick egg membrane, short‐headed sperm) are symplesiomorphies of Spionidae rather than apomorphies of a particular subclade. With the increased use of genomic data, our results advocate for a broader consideration of how assembly and annotation may impact data matrices used in phylogenomic analyses. [ABSTRACT FROM AUTHOR]

Background High-quality genomic resources facilitate investigations into behavioral ecology, morphological and physiological adaptations, and the evolution of genomic architecture. Lizards in the genus Sceloporus have a long history as important ecological, evolutionary, and physiological models, making them a valuable target for the development of genomic resources. Findings We present a high-quality chromosome-level reference genome assembly, SceUnd1.0 (using 10X Genomics Chromium, HiC, and Pacific Biosciences data), and tissue/developmental stage transcriptomes for the eastern fence lizard, Sceloporus undulatus. We performed synteny analysis with other snake and lizard assemblies to identify broad patterns of chromosome evolution including the fusion of micro- and macrochromosomes. We also used this new assembly to provide improved reference-based genome assemblies for 34 additional Sceloporus species. Finally, we used RNAseq and whole-genome resequencing data to compare 3 assemblies, each representing an increased level of cost and effort: Supernova Assembly with data from 10X Genomics Chromium, HiRise Assembly that added data from HiC, and PBJelly Assembly that added data from Pacific Biosciences sequencing. We found that the Supernova Assembly contained the full genome and was a suitable reference for RNAseq and single-nucleotide polymorphism calling, but the chromosome-level scaffolds provided by the addition of HiC data allowed synteny and whole-genome association mapping analyses. The subsequent addition of PacBio data doubled the contig N50 but provided negligible gains in scaffold length. Conclusions These new genomic resources provide valuable tools for advanced molecular analysis of an organism that has become a model in physiology and evolutionary ecology. [ABSTRACT FROM AUTHOR]

Reptiles and other nonmammalian vertebrates have transcriptionally active nucleated red blood cells. If blood transcriptomes can provide quantitative data to address questions relevant to molecular ecology, this could circumvent the need to euthanize animals to assay tissues. This would allow longitudinal sampling of animals' responses to treatments, as well as sampling of protected taxa. We developed and annotated blood transcriptomes from six reptile species and found on average 25,000 proteins are being transcribed in the blood, and there is a CORE group of 9,282 orthogroups that are found in at least four of six species. In comparison to liver transcriptomes from the same taxa, approximately two‐thirds of the orthogroups were found in both blood and liver; and a similar percentage of ecologically relevant gene groups (insulin and insulin‐like signalling, electron transport chain, oxidative stress, glucocorticoid receptors) were found transcribed in both blood and liver. As a resource, we provide a user‐friendly database of gene ids identified in each blood transcriptome. Although on average 37% of reads mapped to haemoglobin, importantly, the majority of nonhaemoglobin transcripts had sufficient depth (e.g., 97% at ≥10 reads) to be included in differential gene expression analysis. Thus, we demonstrate that RNAseq blood transcriptomes from a very small blood sample (<10 μl) is a minimally invasive option in nonmammalian vertebrates for quantifying expression of a large number of ecologically relevant genes that would allow longitudinal sampling and sampling of protected populations. [ABSTRACT FROM AUTHOR]

Deep-sea tubeworms (Annelida, Siboglinidae) represent dominant species in deep-sea chemosynthetic communities (e.g. hydrothermal vents and cold methane seeps) and occur in muddy sediments and organic falls. Siboglinids lack a functional digestive tract as adults, and they rely on endosymbiotic bacteria for energy, making them of evolutionary and physiological interest. Despite their importance, inferred evolutionary history of this group has been inconsistent among studies based on different molecular markers. In particular, placement of bone-eating Osedax worms has been unclear in part because of their distinctive biology, including harbouring heterotrophic bacteria as endosymbionts, displaying extreme sexual dimorphism and exhibiting a distinct body plan. Here, we reconstructed siboglinid evolutionary history using 12 newly sequenced transcriptomes. We parsed data into three data sets that accommodated varying levels of missing data, and we evaluate effects of missing data on phylogenomic inference. Additionally, several multispecies-coalescent approaches and Bayesian concordance analysis ( BCA) were employed to allow for a comparison of results to a supermatrix approach. Every analysis conducted herein strongly supported Osedax being most closely related to the Vestimentifera and Sclerolinum clade, rather than Frenulata, as previously reported. Importantly, unlike previous studies, the alternative hypothesis that frenulates and Osedax are sister groups to one another was explicitly rejected by an approximately unbiased ( AU) test. Furthermore, although different methods showed largely congruent results, we found that a supermatrix method using data partitioning with site-homogenous models potentially outperformed a supermatrix method using the CAT- GTR model and multispecies-coalescent approaches when the amount of missing data varies in a data set and when taxa susceptible to LBA are included in the analyses. [ABSTRACT FROM AUTHOR]