Proc Natl Acad Sci U S A
September 2024
Background: Modern sequencing technologies should make the assembly of the relatively small mitochondrial genomes an easy undertaking. However, few tools exist that address mitochondrial assembly directly.
Results: As part of the Vertebrate Genomes Project (VGP) we develop mitoVGP, a fully automated pipeline for similarity-based identification of mitochondrial reads and de novo assembly of mitochondrial genomes that incorporates both long (> 10 kbp, PacBio or Nanopore) and short (100-300 bp, Illumina) reads.
Mitchell et al. argue that divergence-time estimates for our avian phylogeny were too young because of an "inappropriate" maximum age constraint for the most recent common ancestor of modern birds and that, as a result, most modern bird orders diverged before the Cretaceous-Paleogene mass extinction event 66 million years ago instead of after. However, their interpretations of the fossil record and timetrees are incorrect.
View Article and Find Full Text PDFIn the mutualistic relationship between the squid Euprymna tasmanica and the bioluminescent bacterium Vibrio fischeri, several host factors, including immune-related proteins, are known to interact and respond specifically and exclusively to the presence of the symbiont. In squid and octopus, the white body is considered to be an immune organ mainly due to the fact that blood cells, or hemocytes, are known to be present in high numbers and in different developmental stages. Hence, the white body has been described as the site of hematopoiesis in cephalopods.
View Article and Find Full Text PDFBackground: Determining the evolutionary relationships among the major lineages of extant birds has been one of the biggest challenges in systematic biology. To address this challenge, we assembled or collected the genomes of 48 avian species spanning most orders of birds, including all Neognathae and two of the five Palaeognathae orders. We used these genomes to construct a genome-scale avian phylogenetic tree and perform comparative genomic analyses.
View Article and Find Full Text PDFTo better determine the history of modern birds, we performed a genome-scale phylogenetic analysis of 48 species representing all orders of Neoaves using phylogenomic methods created to handle genome-scale data. We recovered a highly resolved tree that confirms previously controversial sister or close relationships. We identified the first divergence in Neoaves, two groups we named Passerea and Columbea, representing independent lineages of diverse and convergently evolved land and water bird species.
View Article and Find Full Text PDFBirds are the most species-rich class of tetrapod vertebrates and have wide relevance across many research fields. We explored bird macroevolution using full genomes from 48 avian species representing all major extant clades. The avian genome is principally characterized by its constrained size, which predominantly arose because of lineage-specific erosion of repetitive elements, large segmental deletions, and gene loss.
View Article and Find Full Text PDFBackground: The availability of multiple avian genome sequence assemblies greatly improves our ability to define overall genome organization and reconstruct evolutionary changes. In birds, this has previously been impeded by a near intractable karyotype and relied almost exclusively on comparative molecular cytogenetics of only the largest chromosomes. Here, novel whole genome sequence information from 21 avian genome sequences (most newly assembled) made available on an interactive browser (Evolution Highway) was analyzed.
View Article and Find Full Text PDFThere is a growing interest in copy number variation (CNV) and the recognition of its importance in phenotype, disease, adaptation and speciation. CNV data is usually ascertained by array-CGH within-species, but similar inter-species comparisons have also been made in primates, mice and domestic mammals. Here, we conducted a broad appraisal of putative cross-species CNVs in birds, 16 species in all, using the standard array-CGH approach.
View Article and Find Full Text PDFMotivation: Microsatellites are among the most useful genetic markers in population biology. High-throughput sequencing of microsatellite-enriched libraries dramatically expedites the traditional process of screening recombinant libraries for microsatellite markers. However, sorting through millions of reads to distill high-quality polymorphic markers requires special algorithms tailored to tolerate sequencing errors in locus reconstruction, distinguish paralogous loci, rarify raw reads originating from the same amplicon and sort out various artificial fragments resulting from recombination or concatenation of auxiliary adapters.
View Article and Find Full Text PDFBackground: The fat body is the main organ of intermediary metabolism in insects and the principal source of hemolymph proteins. As part of our ongoing efforts to understand mosquito fat body physiology and to identify novel targets for insect control, we have conducted a transcriptome analysis of the fat body of Aedes aegypti before and in response to blood feeding.
Results: We created two fat body non-normalized EST libraries, one from mosquito fat bodies non-blood fed (NBF) and another from mosquitoes 24 hrs post-blood meal (PBM).
Using high resolution X-ray computed tomography data we examined the relationship between cochlear labyrinth volume and body mass in extant, non-primate euarchontoglirans, and in two fossils, to allow for comparison with the results of Kirk and Gosselin-Ildari (2009). Modern primates have significantly higher cochlear labyrinth volumes relative to body mass than other euarchontoglirans, which may be related to a downward shift in the highest and lowest audible frequencies over the course of primate evolution, and to the relative increase in brain size observed in Euprimates.
View Article and Find Full Text PDFOpinions on the systematic relationships of birds in the avian order Gruiformes have been as diverse as the families included within it. Despite ongoing debate over monophyly of the order and relationships among its various members, recent opinion has converged on the monophyly of a "core" group of five families classified as the suborder Grues: the rails (Rallidae), the cranes (Gruidae), the Limpkin (Aramidae), the trumpeters (Psophiidae), and the finfoots (Heliornithidae). We present DNA sequence data from four mitochondrial (cytochrome b, 12S rRNA, Valine tRNA, and 16S rRNA) and three nuclear loci (intron 7 of beta-fibrinogen, intron 5 of alcohol dehydrogenase-I, and introns 3 through 5 of glyceraldehyde-3-phosphate dehydrogenase) to test previous hypotheses of interfamilial relationships within Grues, with particular attention to the enigmatic family Heliornithidae.
View Article and Find Full Text PDFBackground: The phylogeny of shorebirds (Aves: Charadriiformes) and their putative sister groups was reconstructed using approximately 5 kilobases of data from three nuclear loci and two mitochondrial genes, and compared to that based on two other nuclear loci.
Results: Charadriiformes represent a monophyletic group that consists of three monophyletic suborders Lari (i.e.
Knowledge of avian phylogeny is prerequisite to understanding the circumstances and timing of the diversification of birds and the evolution of morphological, behavioral, and life-history traits. Recent molecular datasets have helped to elucidate the three most basal clades in the tree of living birds, but relationships among neoavian orders (the vast majority of birds) remain frustratingly vexing. Here, we examine intron 7 of the beta-fibrinogen gene in the most taxonomically inclusive survey of DNA sequences of nonpasserine bird families and orders to date.
View Article and Find Full Text PDFModern ratites (ostriches, rheas, cassowaries, emus, and kiwis) are flightless birds which have a palatal structure termed 'palaeog-nathous' and are found on daughter-landmasses of the Mesozoic supercontinent Gondwanaland. It has been suggested that a single flightless ancestor, widely distributed in Gondwanaland, gave rise to the various lineages of ratite birds. The temporal calibration of the DNA molecular clock is primarily based on the divergence of ratites, and depends on the validity of this hypothesis.
View Article and Find Full Text PDF