151
|
Abstract
Information about the geological timeframe during which animals radiated into their major subclades is crucial to understanding early animal ecology and evolution. Unfortunately, the pre-Cambrian fossil record is sparse and its interpretation controversial. Relaxed molecular-clock methods provide an alternative means of estimating the timing of cladogenesis deep in the metazoan tree of life. So far, thorough molecular clock studies focusing specifically on Metazoa as a whole have been based on relatively small datasets or incomplete representation of the main non-bilaterian lineages (such as sponges and ctenophores), which are fundamental for understanding early metazoan evolution. Here, we use a previously published phylogenomic dataset that includes a fair sampling of all relevant groups to estimate the timing of early animal evolution with Bayesian relaxed-clock methods. According to our results, all non-bilaterian phyla, as well as total-group Bilateria, evolved in an ancient radiation during a geologically relatively short time span, before the onset of long-term global glaciations (“Snowball Earth”; ~720–635 Ma). Importantly, this result appears robust to alterations of a number of important analytical variables, such as models of among-lineage rate variation and sets of fossil calibrations used.
Collapse
|
152
|
Williams TA, Szöllősi GJ, Spang A, Foster PG, Heaps SE, Boussau B, Ettema TJG, Embley TM. Integrative modeling of gene and genome evolution roots the archaeal tree of life. Proc Natl Acad Sci U S A 2017; 114:E4602-E4611. [PMID: 28533395 PMCID: PMC5468678 DOI: 10.1073/pnas.1618463114] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A root for the archaeal tree is essential for reconstructing the metabolism and ecology of early cells and for testing hypotheses that propose that the eukaryotic nuclear lineage originated from within the Archaea; however, published studies based on outgroup rooting disagree regarding the position of the archaeal root. Here we constructed a consensus unrooted archaeal topology using protein concatenation and a multigene supertree method based on 3,242 single gene trees, and then rooted this tree using a recently developed model of genome evolution. This model uses evidence from gene duplications, horizontal transfers, and gene losses contained in 31,236 archaeal gene families to identify the most likely root for the tree. Our analyses support the monophyly of DPANN (Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota, Nanohaloarchaea), a recently discovered cosmopolitan and genetically diverse lineage, and, in contrast to previous work, place the tree root between DPANN and all other Archaea. The sister group to DPANN comprises the Euryarchaeota and the TACK Archaea, including Lokiarchaeum, which our analyses suggest are monophyletic sister lineages. Metabolic reconstructions on the rooted tree suggest that early Archaea were anaerobes that may have had the ability to reduce CO2 to acetate via the Wood-Ljungdahl pathway. In contrast to proposals suggesting that genome reduction has been the predominant mode of archaeal evolution, our analyses infer a relatively small-genomed archaeal ancestor that subsequently increased in complexity via gene duplication and horizontal gene transfer.
Collapse
Affiliation(s)
- Tom A Williams
- School of Earth Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom;
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Gergely J Szöllősi
- MTA-ELTE Lendület Evolutionary Genomics Research Group, 1117 Budapest, Hungary
| | - Anja Spang
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, SE-75123 Uppsala, Sweden
| | - Peter G Foster
- Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
| | - Sarah E Heaps
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
- School of Mathematics & Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Bastien Boussau
- Univ Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR5558, F-69622 Villeurbanne, France
| | - Thijs J G Ettema
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, SE-75123 Uppsala, Sweden
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| |
Collapse
|
153
|
Anderson FE, Williams BW, Horn KM, Erséus C, Halanych KM, Santos SR, James SW. Phylogenomic analyses of Crassiclitellata support major Northern and Southern Hemisphere clades and a Pangaean origin for earthworms. BMC Evol Biol 2017; 17:123. [PMID: 28558722 PMCID: PMC5450073 DOI: 10.1186/s12862-017-0973-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 05/18/2017] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Earthworms (Crassiclitellata) are a diverse group of annelids of substantial ecological and economic importance. Earthworms are primarily terrestrial infaunal animals, and as such are probably rather poor natural dispersers. Therefore, the near global distribution of earthworms reflects an old and likely complex evolutionary history. Despite a long-standing interest in Crassiclitellata, relationships among and within major clades remain unresolved. METHODS In this study, we evaluate crassiclitellate phylogenetic relationships using 38 new transcriptomes in combination with publicly available transcriptome data. Our data include representatives of nearly all extant earthworm families and a representative of Moniligastridae, another terrestrial annelid group thought to be closely related to Crassiclitellata. We use a series of differentially filtered data matrices and analyses to examine the effects of data partitioning, missing data, compositional and branch-length heterogeneity, and outgroup inclusion. RESULTS AND DISCUSSION We recover a consistent, strongly supported ingroup topology irrespective of differences in methodology. The topology supports two major earthworm clades, each of which consists of a Northern Hemisphere subclade and a Southern Hemisphere subclade. Divergence time analysis results are concordant with the hypothesis that these north-south splits are the result of the breakup of the supercontinent Pangaea. CONCLUSIONS These results support several recently proposed revisions to the classical understanding of earthworm phylogeny, reveal two major clades that seem to reflect Pangaean distributions, and raise new questions about earthworm evolutionary relationships.
Collapse
Affiliation(s)
- Frank E Anderson
- Department of Zoology, Southern Illinois University, Carbondale, IL, 62901, USA.
| | - Bronwyn W Williams
- Department of Zoology, Southern Illinois University, Carbondale, IL, 62901, USA
- North Carolina Museum of Natural Sciences, Research Laboratory, Raleigh, North Carolina, 27699, USA
| | - Kevin M Horn
- Department of Zoology, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Christer Erséus
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30, Göteborg, SE, Sweden
| | - Kenneth M Halanych
- Molette Biology Laboratory for Environmental and Climate Change Studies, Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Scott R Santos
- Molette Biology Laboratory for Environmental and Climate Change Studies, Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Samuel W James
- Department of Biology, University of Iowa, Iowa City, Iowa, 52242, USA
| |
Collapse
|
154
|
Evans SD, Droser ML, Gehling JG. Highly regulated growth and development of the Ediacara macrofossil Dickinsonia costata. PLoS One 2017; 12:e0176874. [PMID: 28520741 PMCID: PMC5435172 DOI: 10.1371/journal.pone.0176874] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/18/2017] [Indexed: 11/21/2022] Open
Abstract
The Ediacara Biota represents the oldest fossil evidence for the appearance of animals but linking these taxa to specific clades has proved challenging. Dickinsonia is an abundant, apparently bilaterally symmetrical Ediacara fossil with uncertain affinities. We identified and measured key morphological features of over 900 specimens of Dickinsonia costata from the Ediacara Member, South Australia to characterize patterns in growth and morphology. Here we show that development in Dickinsonia costata was surprisingly highly regulated to maintain an ovoid shape via terminal addition and the predictable expansion of modules. This result, along with other characters found in Dickinsonia suggests that it does not belong within known animal groups, but that it utilized some of the developmental gene networks of bilaterians, a result predicted by gene sequencing of basal metazoans but previously unidentified in the fossil record. Dickinsonia thus represents an extinct clade located between sponges and the last common ancestor of Protostomes and Deuterostomes, and likely belongs within the Eumetazoa.
Collapse
Affiliation(s)
- Scott D. Evans
- Department of Earth Sciences, University of California at Riverside, Riverside, California, United States of America
- * E-mail:
| | - Mary L. Droser
- Department of Earth Sciences, University of California at Riverside, Riverside, California, United States of America
| | | |
Collapse
|
155
|
Fidler AL, Darris CE, Chetyrkin SV, Pedchenko VK, Boudko SP, Brown KL, Gray Jerome W, Hudson JK, Rokas A, Hudson BG. Collagen IV and basement membrane at the evolutionary dawn of metazoan tissues. eLife 2017; 6. [PMID: 28418331 PMCID: PMC5395295 DOI: 10.7554/elife.24176] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 03/23/2017] [Indexed: 12/13/2022] Open
Abstract
The role of the cellular microenvironment in enabling metazoan tissue genesis remains obscure. Ctenophora has recently emerged as one of the earliest-branching extant animal phyla, providing a unique opportunity to explore the evolutionary role of the cellular microenvironment in tissue genesis. Here, we characterized the extracellular matrix (ECM), with a focus on collagen IV and its variant, spongin short-chain collagens, of non-bilaterian animal phyla. We identified basement membrane (BM) and collagen IV in Ctenophora, and show that the structural and genomic features of collagen IV are homologous to those of non-bilaterian animal phyla and Bilateria. Yet, ctenophore features are more diverse and distinct, expressing up to twenty genes compared to six in vertebrates. Moreover, collagen IV is absent in unicellular sister-groups. Collectively, we conclude that collagen IV and its variant, spongin, are primordial components of the extracellular microenvironment, and as a component of BM, collagen IV enabled the assembly of a fundamental architectural unit for multicellular tissue genesis. DOI:http://dx.doi.org/10.7554/eLife.24176.001 The emergence of the diversity of multicellular animals involved cells joining together to form tissues and organs. The ‘glue’ that enabled the cells to work together is made of rope-like molecules called collagen, which assemble into scaffolds. These smart scaffolds tether proteins forming basement membranes that connect cells, provide strength to tissues, and transmit information that influences how the cells behave. How did collagen evolve over millions of years to enable the ever-increasing complexity, size and diversity of animals? To investigate, Fidler, Darris, Chetyrkin et al. explored the tissues of the most ancient of currently living animals – the comb jellies and sponges. This revealed that among all the collagens that make up the human body, a type called collagen IV was a key innovation that enabled single celled organisms to evolve into multicellular animals. Collagen IV, as molecular glue, enabled the formation of a fundamental architectural unit of basement membrane and cells that allowed multicellular tissues and organs to evolve. The findings presented by Fidler, Darris, Chetyrkin et al. pose questions about how collagen IV glues cells together, and how information is stored in the rope-like scaffolds to influence cell behavior. Understanding these processes could ultimately lead to the development of new treatments for diseases in which the collagen smart scaffolds play a key role, such as in kidney diseases and cancer. DOI:http://dx.doi.org/10.7554/eLife.24176.002
Collapse
Affiliation(s)
- Aaron L Fidler
- Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, United States.,Aspirnaut Program, Vanderbilt University Medical Center, Nashville, United States.,Department of Biological Sciences, Tennessee State University, Nashville, United States
| | - Carl E Darris
- Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, United States
| | - Sergei V Chetyrkin
- Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, United States.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, United States
| | - Vadim K Pedchenko
- Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, United States.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, United States
| | - Sergei P Boudko
- Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, United States.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, United States
| | - Kyle L Brown
- Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, United States.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, United States.,Center for Structural Biology, Vanderbilt University Medical Center, Nashville, United States
| | - W Gray Jerome
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, United States
| | - Julie K Hudson
- Aspirnaut Program, Vanderbilt University Medical Center, Nashville, United States.,Department of Medical Education and Administration, Vanderbilt University Medical Center, Nashville, United States
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University Medical Center, Nashville, United States
| | - Billy G Hudson
- Department of Medicine, Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, United States.,Aspirnaut Program, Vanderbilt University Medical Center, Nashville, United States.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, United States.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, United States.,Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, United States.,Department of Biochemistry, Vanderbilt University Medical Center, Nashville, United States.,Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, United States.,Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, United States
| |
Collapse
|
156
|
Shen XX, Hittinger CT, Rokas A. Contentious relationships in phylogenomic studies can be driven by a handful of genes. Nat Ecol Evol 2017; 1:126. [PMID: 28812701 PMCID: PMC5560076 DOI: 10.1038/s41559-017-0126] [Citation(s) in RCA: 256] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 03/01/2017] [Indexed: 01/05/2023]
Abstract
Phylogenomic studies have resolved countless branches of the tree of life, but remain strongly contradictory on certain, contentious relationships. Here, we use a maximum likelihood framework to quantify the distribution of phylogenetic signal among genes and sites for 17 contentious branches and 6 well-established control branches in plant, animal and fungal phylogenomic data matrices. We find that resolution in some of these 17 branches rests on a single gene or a few sites, and that removal of a single gene in concatenation analyses or a single site from every gene in coalescence-based analyses diminishes support and can alter the inferred topology. These results suggest that tiny subsets of very large data matrices drive the resolution of specific internodes, providing a dissection of the distribution of support and observed incongruence in phylogenomic analyses. We submit that quantifying the distribution of phylogenetic signal in phylogenomic data is essential for evaluating whether branches, especially contentious ones, are truly resolved. Finally, we offer one detailed example of such an evaluation for the controversy regarding the earliest-branching metazoan phylum, for which examination of the distributions of gene-wise and site-wise phylogenetic signal across eight data matrices consistently supports ctenophores as the sister group to all other metazoans.
Collapse
Affiliation(s)
- Xing-Xing Shen
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Chris Todd Hittinger
- Laboratory of Genetics, Genome Center of Wisconsin, DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| |
Collapse
|
157
|
Marino-Puertas L, Goulas T, Gomis-Rüth FX. Matrix metalloproteinases outside vertebrates. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2026-2035. [PMID: 28392403 DOI: 10.1016/j.bbamcr.2017.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 02/07/2023]
Abstract
The matrix metalloproteinase (MMP) family belongs to the metzincin clan of zinc-dependent metallopeptidases. Due to their enormous implications in physiology and disease, MMPs have mainly been studied in vertebrates. They are engaged in extracellular protein processing and degradation, and present extensive paralogy, with 23 forms in humans. One characteristic of MMPs is a ~165-residue catalytic domain (CD), which has been structurally studied for 14 MMPs from human, mouse, rat, pig and the oral-microbiome bacterium Tannerella forsythia. These studies revealed close overall coincidence and characteristic structural features, which distinguish MMPs from other metzincins and give rise to a sequence pattern for their identification. Here, we reviewed the literature available on MMPs outside vertebrates and performed database searches for potential MMP CDs in invertebrates, plants, fungi, viruses, protists, archaea and bacteria. These and previous results revealed that MMPs are widely present in several copies in Eumetazoa and higher plants (Tracheophyta), but have just token presence in eukaryotic algae. A few dozen sequences were found in Ascomycota (within fungi) and in double-stranded DNA viruses infecting invertebrates (within viruses). In contrast, a few hundred sequences were found in archaea and >1000 in bacteria, with several copies for some species. Most of the archaeal and bacterial phyla containing potential MMPs are present in human oral and gut microbiomes. Overall, MMP-like sequences are present across all kingdoms of life, but their asymmetric distribution contradicts the vertical descent model from a eubacterial or archaeal ancestor. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman.
Collapse
Affiliation(s)
- Laura Marino-Puertas
- Proteolysis Lab, Structural Biology Unit, "María-de-Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain
| | - Theodoros Goulas
- Proteolysis Lab, Structural Biology Unit, "María-de-Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain..
| | - F Xavier Gomis-Rüth
- Proteolysis Lab, Structural Biology Unit, "María-de-Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain..
| |
Collapse
|
158
|
Smith CL, Abdallah S, Wong YY, Le P, Harracksingh AN, Artinian L, Tamvacakis AN, Rehder V, Reese TS, Senatore A. Evolutionary insights into T-type Ca 2+ channel structure, function, and ion selectivity from the Trichoplax adhaerens homologue. J Gen Physiol 2017; 149:483-510. [PMID: 28330839 PMCID: PMC5379919 DOI: 10.1085/jgp.201611683] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 02/07/2017] [Indexed: 12/31/2022] Open
Abstract
The role of T-type calcium channels in animals without nervous systems is unknown. Smith et al. characterize TCav3 from Trichoplax adhaerens, finding expression in neurosecretory-like cells and preference for Ca2+ over Na+ via strong extracellular Ca2+ block, despite low selectivity for Ca2+ in the pore. Four-domain voltage-gated Ca2+ (Cav) channels play fundamental roles in the nervous system, but little is known about when or how their unique properties and cellular roles evolved. Of the three types of metazoan Cav channels, Cav1 (L-type), Cav2 (P/Q-, N- and R-type) and Cav3 (T-type), Cav3 channels are optimized for regulating cellular excitability because of their fast kinetics and low activation voltages. These same properties permit Cav3 channels to drive low-threshold exocytosis in select neurons and neurosecretory cells. Here, we characterize the single T-type calcium channel from Trichoplax adhaerens (TCav3), an early diverging animal that lacks muscle, neurons, and synapses. Co-immunolocalization using antibodies against TCav3 and neurosecretory cell marker complexin labeled gland cells, which are hypothesized to play roles in paracrine signaling. Cloning and in vitro expression of TCav3 reveals that, despite roughly 600 million years of divergence from other T-type channels, it bears the defining structural and biophysical features of the Cav3 family. We also characterize the channel’s cation permeation properties and find that its pore is less selective for Ca2+ over Na+ compared with the human homologue Cav3.1, yet it exhibits a similar potent block of inward Na+ current by low external Ca2+ concentrations (i.e., the Ca2+ block effect). A comparison of the permeability features of TCav3 with other cloned channels suggests that Ca2+ block is a locus of evolutionary change in T-type channel cation permeation properties and that mammalian channels distinguish themselves from invertebrate ones by bearing both stronger Ca2+ block and higher Ca2+ selectivity. TCav3 is the most divergent metazoan T-type calcium channel and thus provides an evolutionary perspective on Cav3 channel structure–function properties, ion selectivity, and cellular physiology.
Collapse
Affiliation(s)
- Carolyn L Smith
- National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Salsabil Abdallah
- University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Yuen Yan Wong
- University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Phuong Le
- University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | | | | | | | | | - Thomas S Reese
- National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Adriano Senatore
- University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| |
Collapse
|
159
|
A Large and Consistent Phylogenomic Dataset Supports Sponges as the Sister Group to All Other Animals. Curr Biol 2017; 27:958-967. [PMID: 28318975 DOI: 10.1016/j.cub.2017.02.031] [Citation(s) in RCA: 282] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/07/2017] [Accepted: 02/13/2017] [Indexed: 01/11/2023]
Abstract
Resolving the early diversification of animal lineages has proven difficult, even using genome-scale datasets. Several phylogenomic studies have supported the classical scenario in which sponges (Porifera) are the sister group to all other animals ("Porifera-sister" hypothesis), consistent with a single origin of the gut, nerve cells, and muscle cells in the stem lineage of eumetazoans (bilaterians + ctenophores + cnidarians). In contrast, several other studies have recovered an alternative topology in which ctenophores are the sister group to all other animals (including sponges). The "Ctenophora-sister" hypothesis implies that eumetazoan-specific traits, such as neurons and muscle cells, either evolved once along the metazoan stem lineage and were then lost in sponges and placozoans or evolved at least twice independently in Ctenophora and in Cnidaria + Bilateria. Here, we report on our reconstruction of deep metazoan relationships using a 1,719-gene dataset with dense taxonomic sampling of non-bilaterian animals that was assembled using a semi-automated procedure, designed to reduce known error sources. Our dataset outperforms previous metazoan gene superalignments in terms of data quality and quantity. Analyses with a best-fitting site-heterogeneous evolutionary model provide strong statistical support for placing sponges as the sister-group to all other metazoans, with ctenophores emerging as the second-earliest branching animal lineage. Only those methodological settings that exacerbated long-branch attraction artifacts yielded Ctenophora-sister. These results show that methodological issues must be carefully addressed to tackle difficult phylogenetic questions and pave the road to a better understanding of how fundamental features of animal body plans have emerged.
Collapse
|
160
|
Mills DB, Canfield DE. A trophic framework for animal origins. GEOBIOLOGY 2017; 15:197-210. [PMID: 27686422 DOI: 10.1111/gbi.12216] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/25/2016] [Indexed: 06/06/2023]
Abstract
Metazoans emerged in a microbial world and play a unique role in the biosphere as the only complex multicellular eukaryotes capable of phagocytosis. While the bodyplan and feeding mode of the last common metazoan ancestor remain unresolved, the earliest multicellular stem-metazoans likely subsisted on picoplankton (planktonic microbes 0.2-2 μm in diameter) and dissolved organic matter (DOM), similarly to modern sponges. Once multicellular stem-metazoans emerged, they conceivably modulated both the local availability of picoplankton, which they preferentially removed from the water column for feeding, and detrital particles 2-100 μm in diameter, which they expelled and deposited into the benthos as waste products. By influencing the availability of these heterotrophic food sources, the earliest multicellular stem-metazoans would have acted as ecosystem engineers, helping create the ecological conditions under which other metazoans, namely detritivores and non-sponge suspension feeders incapable of subsisting on picoplankton and DOM, could emerge and diversify. This early style of metazoan feeding, specifically the phagocytosis of small eukaryotic prey, could have also encouraged the evolution of larger, even multicellular, eukaryotic forms less prone to metazoan consumption. Therefore, the first multicellular stem-metazoans, through their feeding, arguably helped bridge the strictly microbial food webs of the Proterozoic Eon (2.5-0.541 billion years ago) to the more macroscopic, metazoan-sustaining food webs of the Phanerozoic Eon (0.541-0 billion years ago).
Collapse
Affiliation(s)
- D B Mills
- Department of Biology, Nordic Center for Earth Evolution, University of Southern Denmark, Odense, Denmark
| | - D E Canfield
- Department of Biology, Nordic Center for Earth Evolution, University of Southern Denmark, Odense, Denmark
| |
Collapse
|
161
|
Liszewski MK, Elvington M, Kulkarni HS, Atkinson JP. Complement's hidden arsenal: New insights and novel functions inside the cell. Mol Immunol 2017; 84:2-9. [PMID: 28196665 DOI: 10.1016/j.molimm.2017.01.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/07/2017] [Indexed: 12/31/2022]
Abstract
A key component of both innate and adaptive immunity, new understandings of the complement system are expanding its roles beyond that traditionally appreciated. Evidence is accumulating that complement has an intracellular arsenal of components that provide not only immune defense, but also assist in key interactions for host cell functions. Although early work has primarily centered on T cells, the intracellular complement system likely functions in many if not most cells of the body. Some of these functions may trace their origins to the primitive complement system that began as a primeval form of C3 likely tasked for protection from intracellular pathogen invasion. This later expanded to include extracellular defense as C3 became a secreted protein to patrol the vasculature. Other components were added to the growing system including regulators to protect host cells from the indiscriminate effects of this potent system. Contemporary cells may retain some of these vestigial remnants. We now know that a) C3 serves as a damage-associated molecular pattern (in particular by coating pathogens that translocate into cells), b) most cells store C3 and recycle C3(H2O) for immediate use, and c) C3 assists in cellular survival and metabolic reprogramming. Other components also are part of this hidden arsenal including C5, properdin, factors H and B, and complement receptors. Importantly, better definition of the intracellular complement system may translate into new target discovery to assist in creating the next generation of complement therapeutics.
Collapse
Affiliation(s)
| | | | - Hrishikesh S Kulkarni
- Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, Campus Box 8045, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | | |
Collapse
|
162
|
Abstract
The leap from simple unicellularity to complex multicellularity remains one of life's major enigmas. The origins of metazoan developmental gene regulatory mechanisms are sought by analyzing gene regulation in extant eumetazoans, sponges, and unicellular organisms. The main hypothesis of this manuscript is that, developmental enhancers evolved from unicellular inducible promoters that diversified the expression of regulatory genes during metazoan evolution. Promoters and enhancers are functionally similar; both can regulate the transcription of distal promoters and both direct local transcription. Additionally, enhancers have experimentally characterized structural features that reveal their origin from inducible promoters. The distal co-operative regulation among promoters identified in unicellular opisthokonts possibly represents the precursor of distal regulation of promoters by enhancers. During metazoan evolution, constitutive-type promoters of regulatory genes would have acquired novel receptivity to distal regulatory inputs from promoters of inducible genes that eventually specialized as enhancers. The novel regulatory interactions would have caused constitutively expressed genes controlling differential gene expression in unicellular organisms to become themselves differentially expressed. The consequence of the novel regulatory interactions was that regulatory pathways of unicellular organisms became interlaced and ultimately evolved into the intricate developmental gene regulatory networks (GRNs) of extant metazoans.
Collapse
Affiliation(s)
- César Arenas-Mena
- Department of Biology, College of Staten Island and Graduate Center, The City University of New York (CUNY), Staten Island, NY 10314, USA
| |
Collapse
|
163
|
Cramer JM, Pohlmann D, Gomez F, Mark L, Kornegay B, Hall C, Siraliev-Perez E, Walavalkar NM, Sperlazza MJ, Bilinovich S, Prokop JW, Hill AL, Williams Jr. DC. Methylation specific targeting of a chromatin remodeling complex from sponges to humans. Sci Rep 2017; 7:40674. [PMID: 28094816 PMCID: PMC5240623 DOI: 10.1038/srep40674] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 12/09/2016] [Indexed: 12/31/2022] Open
Abstract
DNA cytosine methylation and methyl-cytosine binding domain (MBD) containing proteins are found throughout all vertebrate species studied to date. However, both the presence of DNA methylation and pattern of methylation varies among invertebrate species. Invertebrates generally have only a single MBD protein, MBD2/3, that does not always contain appropriate residues for selectively binding methylated DNA. Therefore, we sought to determine whether sponges, one of the most ancient extant metazoan lineages, possess an MBD2/3 capable of recognizing methylated DNA and recruiting the associated nucleosome remodeling and deacetylase (NuRD) complex. We find that Ephydatia muelleri has genes for each of the NuRD core components including an EmMBD2/3 that selectively binds methylated DNA. NMR analyses reveal a remarkably conserved binding mode, showing almost identical chemical shift changes between binding to methylated and unmethylated CpG dinucleotides. In addition, we find that EmMBD2/3 and EmGATAD2A/B proteins form a coiled-coil interaction known to be critical for the formation of NuRD. Finally, we show that knockdown of EmMBD2/3 expression disrupts normal cellular architecture and development of E. muelleri. These data support a model in which the MBD2/3 methylation-dependent functional role emerged with the earliest multicellular organisms and has been maintained to varying degrees across animal evolution.
Collapse
Affiliation(s)
- Jason M. Cramer
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA
| | - Deborah Pohlmann
- Department of Biology, University of Richmond, Richmond, VA, USA
| | - Fernando Gomez
- Department of Biology, University of Richmond, Richmond, VA, USA
| | - Leslie Mark
- Department of Biology, University of Richmond, Richmond, VA, USA
| | | | - Chelsea Hall
- Department of Biology, University of Richmond, Richmond, VA, USA
| | - Edhriz Siraliev-Perez
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ninad M. Walavalkar
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - M. Jeannette Sperlazza
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Stephanie Bilinovich
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - April L. Hill
- Department of Biology, University of Richmond, Richmond, VA, USA
| | - David C. Williams Jr.
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| |
Collapse
|
164
|
Arcila D, Ortí G, Vari R, Armbruster JW, Stiassny MLJ, Ko KD, Sabaj MH, Lundberg J, Revell LJ, Betancur-R R. Genome-wide interrogation advances resolution of recalcitrant groups in the tree of life. Nat Ecol Evol 2017; 1:20. [PMID: 28812610 DOI: 10.1038/s41559-016-0020] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 10/25/2016] [Indexed: 12/21/2022]
Abstract
Much progress has been achieved in disentangling evolutionary relationships among species in the tree of life, but some taxonomic groups remain difficult to resolve despite increasing availability of genome-scale data sets. Here we present a practical approach to studying ancient divergences in the face of high levels of conflict, based on explicit gene genealogy interrogation (GGI). We show its efficacy in resolving the controversial relationships within the largest freshwater fish radiation (Otophysi) based on newly generated DNA sequences for 1,051 loci from 225 species. Initial results using a suite of standard methodologies revealed conflicting phylogenetic signal, which supports ten alternative evolutionary histories among early otophysan lineages. By contrast, GGI revealed that the vast majority of gene genealogies supports a single tree topology grounded on morphology that was not obtained by previous molecular studies. We also reanalysed published data sets for exemplary groups with recalcitrant resolution to assess the power of this approach. GGI supports the notion that ctenophores are the earliest-branching animal lineage, and adds insight into relationships within clades of yeasts, birds and mammals. GGI opens up a promising avenue to account for incompatible signals in large data sets and to discern between estimation error and actual biological conflict explaining gene tree discordance.
Collapse
Affiliation(s)
- Dahiana Arcila
- Department of Biological Sciences, The George Washington University, 2023 G Street NW, Washington DC 20052, USA.,Department of Vertebrate Zoology, National Museum of Natural History Smithsonian Institution, PO Box 37012, MRC 159, Washington DC 20013, USA
| | - Guillermo Ortí
- Department of Biological Sciences, The George Washington University, 2023 G Street NW, Washington DC 20052, USA
| | - Richard Vari
- Department of Vertebrate Zoology, National Museum of Natural History Smithsonian Institution, PO Box 37012, MRC 159, Washington DC 20013, USA
| | | | - Melanie L J Stiassny
- Department of Ichthyology, Division of Vertebrate Zoology, American Museum of Natural History, New York, New York 10024, USA
| | - Kyung D Ko
- Department of Biological Sciences, The George Washington University, 2023 G Street NW, Washington DC 20052, USA
| | - Mark H Sabaj
- Department of Ichthyology, The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania 19103, USA
| | - John Lundberg
- Department of Ichthyology, The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania 19103, USA
| | - Liam J Revell
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts 02125, USA
| | - Ricardo Betancur-R
- Department of Vertebrate Zoology, National Museum of Natural History Smithsonian Institution, PO Box 37012, MRC 159, Washington DC 20013, USA.,Department of Biology, University of Puerto Rico - Río Piedras, PO Box 23360, San Juan, Puerto Rico
| |
Collapse
|
165
|
Redmond AK, Pettinello R, Dooley H. Outgroup, alignment and modelling improvements indicate that two TNFSF13-like genes existed in the vertebrate ancestor. Immunogenetics 2017; 69:187-192. [PMID: 28070614 PMCID: PMC5316386 DOI: 10.1007/s00251-016-0967-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 12/26/2016] [Indexed: 11/30/2022]
Abstract
The molecular machinery required for lymphocyte development and differentiation appears to have emerged concomitantly with distinct B- and T-like lymphocyte subsets in the ancestor of all vertebrates. The TNFSF superfamily (TNFSF) members BAFF (TNFSF13/Blys) and APRIL (TNFSF13) are key regulators of B cell development survival, and activation in mammals, but the temporal emergence of these molecules, and their precise relationship to the newly identified TNFSF gene BALM (BAFF and APRIL-like molecule), have not yet been elucidated. Here, to resolve the early evolutionary history of this family, we improved outgroup sampling and alignment quality, and applied better fitting substitution models compared to past studies. Our analyses reveal that BALM is a definitive TNFSF13 family member, which split from BAFF in the gnathostome (jawed vertebrate) ancestor. Most importantly, however, we show that both the APRIL and BAFF lineages existed in the ancestors of all extant vertebrates. This implies that APRIL has been lost, or is yet to be found, in cyclostomes (jawless vertebrates). Our results suggest that lineage-specific gene duplication and loss events have caused lymphocyte regulation, despite shared origins, to become secondarily distinct between gnathostomes and cyclostomes. Finally, the structure of lamprey BAFF-like, and its phylogenetic placement as sister to BAFF and BALM, but not the more slowly evolving APRIL, indicates that the primordial lymphocyte regulator was more APRIL-like than BAFF-like.
Collapse
Affiliation(s)
- Anthony K Redmond
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK.,Centre for Genome-Enabled Biology & Medicine, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - Rita Pettinello
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - Helen Dooley
- School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK. .,Dept. Microbiology & Immunology, Institute of Marine & Environmental Technology, University of Maryland School of Medicine, 701 E. Pratt Street, Baltimore, MD21202, USA.
| |
Collapse
|
166
|
Holzer G, Markov GV, Laudet V. Evolution of Nuclear Receptors and Ligand Signaling. Curr Top Dev Biol 2017; 125:1-38. [DOI: 10.1016/bs.ctdb.2017.02.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
167
|
Phylogenomics and species delimitation in the knob-scaled lizards of the genus Xenosaurus (Squamata: Xenosauridae) using ddRADseq data reveal a substantial underestimation of diversity. Mol Phylogenet Evol 2017; 106:241-253. [DOI: 10.1016/j.ympev.2016.09.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 08/03/2016] [Accepted: 09/01/2016] [Indexed: 11/24/2022]
|
168
|
Sebé-Pedrós A, Ruiz-Trillo I. Evolution and Classification of the T-Box Transcription Factor Family. Curr Top Dev Biol 2017; 122:1-26. [DOI: 10.1016/bs.ctdb.2016.06.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
169
|
Cunningham JA, Liu AG, Bengtson S, Donoghue PCJ. The origin of animals: Can molecular clocks and the fossil record be reconciled? Bioessays 2016; 39:1-12. [PMID: 27918074 DOI: 10.1002/bies.201600120] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The evolutionary emergence of animals is one of the most significant episodes in the history of life, but its timing remains poorly constrained. Molecular clocks estimate that animals originated and began diversifying over 100 million years before the first definitive metazoan fossil evidence in the Cambrian. However, closer inspection reveals that clock estimates and the fossil record are less divergent than is often claimed. Modern clock analyses do not predict the presence of the crown-representatives of most animal phyla in the Neoproterozoic. Furthermore, despite challenges provided by incomplete preservation, a paucity of phylogenetically informative characters, and uncertain expectations of the anatomy of early animals, a number of Neoproterozoic fossils can reasonably be interpreted as metazoans. A considerable discrepancy remains, but much of this can be explained by the limited preservation potential of early metazoans and the difficulties associated with their identification in the fossil record. Critical assessment of both records may permit better resolution of the tempo and mode of early animal evolution.
Collapse
Affiliation(s)
- John A Cunningham
- School of Earth Sciences, University of Bristol, Bristol, UK.,Department of Palaeobiology and Nordic Center for Earth Evolution, Swedish Museum of Natural History, Stockholm, Sweden
| | - Alexander G Liu
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - Stefan Bengtson
- Department of Palaeobiology and Nordic Center for Earth Evolution, Swedish Museum of Natural History, Stockholm, Sweden
| | | |
Collapse
|
170
|
Petralia RS, Wang YX, Mattson MP, Yao PJ. The Diversity of Spine Synapses in Animals. Neuromolecular Med 2016; 18:497-539. [PMID: 27230661 PMCID: PMC5158183 DOI: 10.1007/s12017-016-8405-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/11/2016] [Indexed: 12/23/2022]
Abstract
Here we examine the structure of the various types of spine synapses throughout the animal kingdom. Based on available evidence, we suggest that there are two major categories of spine synapses: invaginating and non-invaginating, with distributions that vary among different groups of animals. In the simplest living animals with definitive nerve cells and synapses, the cnidarians and ctenophores, most chemical synapses do not form spine synapses. But some cnidarians have invaginating spine synapses, especially in photoreceptor terminals of motile cnidarians with highly complex visual organs, and also in some mainly sessile cnidarians with rapid prey capture reflexes. This association of invaginating spine synapses with complex sensory inputs is retained in the evolution of higher animals in photoreceptor terminals and some mechanoreceptor synapses. In contrast to invaginating spine synapse, non-invaginating spine synapses have been described only in animals with bilateral symmetry, heads and brains, associated with greater complexity in neural connections. This is apparent already in the simplest bilaterians, the flatworms, which can have well-developed non-invaginating spine synapses in some cases. Non-invaginating spine synapses diversify in higher animal groups. We also discuss the functional advantages of having synapses on spines and more specifically, on invaginating spines. And finally we discuss pathologies associated with spine synapses, concentrating on those systems and diseases where invaginating spine synapses are involved.
Collapse
Affiliation(s)
- Ronald S Petralia
- Advanced Imaging Core, NIDCD/NIH, 35A Center Drive, Room 1E614, Bethesda, MD, 20892-3729, USA.
| | - Ya-Xian Wang
- Advanced Imaging Core, NIDCD/NIH, 35A Center Drive, Room 1E614, Bethesda, MD, 20892-3729, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
| | - Pamela J Yao
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA
| |
Collapse
|
171
|
Kjer K, Borowiec ML, Frandsen PB, Ware J, Wiegmann BM. Advances using molecular data in insect systematics. CURRENT OPINION IN INSECT SCIENCE 2016; 18:40-47. [PMID: 27939709 DOI: 10.1016/j.cois.2016.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 09/26/2016] [Indexed: 06/06/2023]
Abstract
The size of molecular datasets has been growing exponentially since the mid 1980s, and new technologies have now dramatically increased the slope of this increase. New datasets include genomes, transcriptomes, and hybrid capture data, producing hundreds or thousands of loci. With these datasets, we are approaching a consensus on the higher level insect phylogeny. Huge datasets can produce new challenges in interpreting branch support, and new opportunities in developing better models and more sophisticated partitioning schemes. Dating analyses are improving as we recognize the importance of careful fossil calibration selection. With thousands of genes now available, coalescent methods have come of age. Barcode libraries continue to expand, and new methods are being developed for incorporating them into phylogenies with tens of thousands of individuals.
Collapse
Affiliation(s)
- Karl Kjer
- Rutgers University, Department of Biological Sciences, 415 Boyden Hall, Newark, NJ 07012, USA
| | - Marek L Borowiec
- University of Rochester, 226 Hutchison Hall, Rochester, NY 14627, USA
| | - Paul B Frandsen
- Smithsonian Institution, Office of Research Information Services, Office of the Chief Information Officer, Washington, D.C. 20024, USA
| | - Jessica Ware
- Rutgers University, Department of Biological Sciences, 415 Boyden Hall, Newark, NJ 07012, USA
| | - Brian M Wiegmann
- Department of Entomology & Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA.
| |
Collapse
|
172
|
Kirkegaard JB, Bouillant A, Marron AO, Leptos KC, Goldstein RE. Aerotaxis in the closest relatives of animals. eLife 2016; 5. [PMID: 27882869 PMCID: PMC5122458 DOI: 10.7554/elife.18109] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 10/17/2016] [Indexed: 12/19/2022] Open
Abstract
As the closest unicellular relatives of animals, choanoflagellates serve as useful model organisms for understanding the evolution of animal multicellularity. An important factor in animal evolution was the increasing ocean oxygen levels in the Precambrian, which are thought to have influenced the emergence of complex multicellular life. As a first step in addressing these conditions, we study here the response of the colony-forming choanoflagellate Salpingoeca rosetta to oxygen gradients. Using a microfluidic device that allows spatio-temporal variations in oxygen concentrations, we report the discovery that S. rosetta displays positive aerotaxis. Analysis of the spatial population distributions provides evidence for logarithmic sensing of oxygen, which enhances sensing in low oxygen neighborhoods. Analysis of search strategy models on the experimental colony trajectories finds that choanoflagellate aerotaxis is consistent with stochastic navigation, the statistics of which are captured using an effective continuous version based on classical run-and-tumble chemotaxis. DOI:http://dx.doi.org/10.7554/eLife.18109.001 Most animals are made up of millions of cells, yet all animals evolved from ancestors that spent their whole lives as single cells. Today the closest single-celled relatives of animals are a group of aquatic organisms called choanoflagellates. Certain species of choanoflagellates can also form swimming colonies. This kind of multicellularity might resemble that seen in the earliest of animals. As such, studies into modern-day choanoflagellates can give insights into how the first animals to evolve might have behaved. Many organisms can find their way towards favorable areas using different strategies. For instance, bacteria can bias their tumbling to gradually swim towards food, and algae can turn and move directly towards light. While choanoflagellates require oxygen, it was not known if they could also actively navigate towards it, or any other resource. Now, Kirkegaard et al. find that the choanoflagellate Salpingoeca rosetta can indeed navigate towards oxygen – an ability called aerotaxis. This was true for both individual cells and for colonies made up of many cells. This discovery suggests that the transition from living as a single cell to living as a simple multicellular organism could still have allowed the earliest animals to seek out and move towards resource-rich areas. Aerotaxis requires cells to both sense oxygen and react appropriately to changes in its concentration. Kirkegaard et al. watched choanoflagellate colonies swimming under controlled conditions and varied the oxygen concentration in the water over time. These experiments revealed that the colonies navigate based on the logarithm of the oxygen concentration, so that at low oxygen levels the cells were even more sensitive to small changes in oxygen concentration. This type of ‘logarithmic sensing’ is similar to how our ears sense sounds and our eyes sense light. Kirkegaard et al. went on to conclude that the colonies were not actively steering in the correct direction directly. Instead, the colonies appeared to choose directions at random and later decide whether such a turn was correct. It remains unclear whether the common ancestor of animals and choanoflagellates could also perform aerotaxis, and if so what mechanisms this involved. Further studies to compare aerotaxis and aerotaxis-related genes in simple animals and other single-celled relatives of animals would be needed to illuminate this. Future studies could also explore the maximum and minimum oxygen concentrations that choanoflagellates can detect, and how well they navigate at these upper and lower limits. DOI:http://dx.doi.org/10.7554/eLife.18109.002
Collapse
Affiliation(s)
- Julius B Kirkegaard
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Ambre Bouillant
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Alan O Marron
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Kyriacos C Leptos
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Raymond E Goldstein
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
173
|
Senatore A, Raiss H, Le P. Physiology and Evolution of Voltage-Gated Calcium Channels in Early Diverging Animal Phyla: Cnidaria, Placozoa, Porifera and Ctenophora. Front Physiol 2016; 7:481. [PMID: 27867359 PMCID: PMC5095125 DOI: 10.3389/fphys.2016.00481] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 10/07/2016] [Indexed: 12/18/2022] Open
Abstract
Voltage-gated calcium (Cav) channels serve dual roles in the cell, where they can both depolarize the membrane potential for electrical excitability, and activate transient cytoplasmic Ca2+ signals. In animals, Cav channels play crucial roles including driving muscle contraction (excitation-contraction coupling), gene expression (excitation-transcription coupling), pre-synaptic and neuroendocrine exocytosis (excitation-secretion coupling), regulation of flagellar/ciliary beating, and regulation of cellular excitability, either directly or through modulation of other Ca2+-sensitive ion channels. In recent years, genome sequencing has provided significant insights into the molecular evolution of Cav channels. Furthermore, expanded gene datasets have permitted improved inference of the species phylogeny at the base of Metazoa, providing clearer insights into the evolution of complex animal traits which involve Cav channels, including the nervous system. For the various types of metazoan Cav channels, key properties that determine their cellular contribution include: Ion selectivity, pore gating, and, importantly, cytoplasmic protein-protein interactions that direct sub-cellular localization and functional complexing. It is unclear when these defining features, many of which are essential for nervous system function, evolved. In this review, we highlight some experimental observations that implicate Cav channels in the physiology and behavior of the most early-diverging animals from the phyla Cnidaria, Placozoa, Porifera, and Ctenophora. Given our limited understanding of the molecular biology of Cav channels in these basal animal lineages, we infer insights from better-studied vertebrate and invertebrate animals. We also highlight some apparently conserved cellular functions of Cav channels, which might have emerged very early on during metazoan evolution, or perhaps predated it.
Collapse
Affiliation(s)
- Adriano Senatore
- Department of Biology, University of Toronto Mississauga Mississauga, ON, Canada
| | - Hamad Raiss
- Department of Biology, University of Toronto Mississauga Mississauga, ON, Canada
| | - Phuong Le
- Department of Biology, University of Toronto Mississauga Mississauga, ON, Canada
| |
Collapse
|
174
|
Abstract
Ctenophores, one of the most basal branches in the tree of life, have been found to have a through-gut, complete with mouth and anus. Basal animals are surprisingly complex and simplification has been rampant in animal evolution.
Collapse
Affiliation(s)
- Gonzalo Giribet
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, 26 Oxford Street, Cambridge, MA 02138, USA.
| |
Collapse
|
175
|
Fortunato SAV, Vervoort M, Adamski M, Adamska M. Conservation and divergence of bHLH genes in the calcisponge Sycon ciliatum. EvoDevo 2016; 7:23. [PMID: 27757221 PMCID: PMC5064789 DOI: 10.1186/s13227-016-0060-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/27/2016] [Indexed: 12/18/2022] Open
Abstract
Background Basic Helix-Loop-Helix (bHLH) genes encode a large family of eukaryotic transcription factors, categorized into six high-order groups: pan-eukaryotic group B involved in regulation of cell cycle, metabolism, and development; holozoan-specific groups C and F involved in development and maintenance of homeostasis; and metazoan-specific groups A, D and E including well-studied genes, such as Atonal, Twist and Hairy, with diverse developmental roles including control of morphogenesis and specification of neurons. Current scenarios of bHLH evolution in animals are mainly based on the bHLH gene set found in the genome of demosponge Amphimedon queenslandica. In this species, the majority of the 21 identified bHLH genes belong to group B, and the single group A gene is orthologous to several neurogenic bilaterian subfamilies, including atonal and neurogenin. Results Given recently discovered differences in developmental toolkit components between siliceous and calcareous sponges, we have carried out genome-wide analysis of bHLH genes in Sycon ciliatum, an emerging calcisponge model. We identified 30 bHLH genes in this species, representing 12 individual families, including four group A families not found in Amphimedon, and two larger family groupings. Notably, the families represented in Sycon are only partially overlapping with those represented in Amphimedon. Developmental expression analysis of a subset of the identified genes revealed patterns consistent with deeply conserved roles, such as specification of sensory cells by Atona-related and stem cells by Myc genes. Conclusions Our results demonstrate independent gene loss events in demosponges and calcisponges, implying a complex bHLH toolkit in the last common metazoan ancestor. Electronic supplementary material The online version of this article (doi:10.1186/s13227-016-0060-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Sofia A V Fortunato
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,ARC Centre for Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811 Australia
| | - Michel Vervoort
- Institut Jacques Monod - CNRS, Université Paris Diderot, 75005 Paris Cedex 13, France
| | - Marcin Adamski
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,Research School of Biology, Australian National University, Canberra, Australia
| | - Maja Adamska
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.,Research School of Biology, Australian National University, Canberra, Australia
| |
Collapse
|
176
|
Mulcahy DG, Macdonald KS, Brady SG, Meyer C, Barker KB, Coddington J. Greater than X kb: a quantitative assessment of preservation conditions on genomic DNA quality, and a proposed standard for genome-quality DNA. PeerJ 2016; 4:e2528. [PMID: 27761327 DOI: 10.7287/peerj.preprints.2202v1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/04/2016] [Indexed: 05/26/2023] Open
Abstract
Advances in biodiversity genomic sequencing will increasingly depend on the availability of DNA samples-and their quantifiable metadata-preserved in large institutional biorepositories that are discoverable to the scientific community. Improvements in sequencing technology constantly provide longer reads, such that longer fragment length, higher molecular weight, and overall "genome-quality" DNA (gDNA) will be desirable. Ideally, biorepositories should publish numerical scale measurements of DNA quality useful to the user community. However, the most widely used technique to evaluate DNA quality, the classic agarose gel, has yet to be quantified. Here we propose a simple and economical method using open source image analysis software to make gDNA gel images quantifiable, and propose percentage of gDNA "greater than X kb" as a standard of comparison, where X is a band from any widely used DNA ladder with desirably large band sizes. We employ two metadata standards ("DNA Threshold" and "Percent above Threshold") introduced as part of the Global Genome Biodiversity Network (GGBN) Darwin Core extension. We illustrate the method using the traditionally used HindIII ladder and the 9,416 base-pair (bp) band as a standard. We also present data, for two taxa, a vertebrate (fish) and an invertebrate (crab), on how gDNA quality varies with seven tissue preservation methods, time since death, preservation method (i.e. buffers vs. cold temperatures), and storage temperature of various buffers over time. Our results suggest that putting tissue into a buffer prior to freezing may be better than directly into ultra-cold conditions.
Collapse
Affiliation(s)
- Daniel G Mulcahy
- Global Genome Initiative, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Kenneth S Macdonald
- Laboratories of Analytical Biology, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Seán G Brady
- Department of Entomology, National Museum of Natural History, Smithsonian Institution , Washingtion, DC , USA
| | - Christopher Meyer
- Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Katharine B Barker
- Global Genome Initiative, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Jonathan Coddington
- Global Genome Initiative, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA; Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washingtion, DC, USA
| |
Collapse
|
177
|
Mulcahy DG, Macdonald KS, Brady SG, Meyer C, Barker KB, Coddington J. Greater than X kb: a quantitative assessment of preservation conditions on genomic DNA quality, and a proposed standard for genome-quality DNA. PeerJ 2016; 4:e2528. [PMID: 27761327 PMCID: PMC5068448 DOI: 10.7717/peerj.2528] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/04/2016] [Indexed: 12/02/2022] Open
Abstract
Advances in biodiversity genomic sequencing will increasingly depend on the availability of DNA samples—and their quantifiable metadata—preserved in large institutional biorepositories that are discoverable to the scientific community. Improvements in sequencing technology constantly provide longer reads, such that longer fragment length, higher molecular weight, and overall “genome-quality” DNA (gDNA) will be desirable. Ideally, biorepositories should publish numerical scale measurements of DNA quality useful to the user community. However, the most widely used technique to evaluate DNA quality, the classic agarose gel, has yet to be quantified. Here we propose a simple and economical method using open source image analysis software to make gDNA gel images quantifiable, and propose percentage of gDNA “greater than X kb” as a standard of comparison, where X is a band from any widely used DNA ladder with desirably large band sizes. We employ two metadata standards (“DNA Threshold” and “Percent above Threshold”) introduced as part of the Global Genome Biodiversity Network (GGBN) Darwin Core extension. We illustrate the method using the traditionally used HindIII ladder and the 9,416 base-pair (bp) band as a standard. We also present data, for two taxa, a vertebrate (fish) and an invertebrate (crab), on how gDNA quality varies with seven tissue preservation methods, time since death, preservation method (i.e. buffers vs. cold temperatures), and storage temperature of various buffers over time. Our results suggest that putting tissue into a buffer prior to freezing may be better than directly into ultra-cold conditions.
Collapse
Affiliation(s)
- Daniel G Mulcahy
- Global Genome Initiative, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Kenneth S Macdonald
- Laboratories of Analytical Biology, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Seán G Brady
- Department of Entomology, National Museum of Natural History, Smithsonian Institution , Washingtion, DC , USA
| | - Christopher Meyer
- Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Katharine B Barker
- Global Genome Initiative, National Museum of Natural History, Smithsonian Institution , Washington, DC , USA
| | - Jonathan Coddington
- Global Genome Initiative, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA; Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washingtion, DC, USA
| |
Collapse
|
178
|
Gold DA, O'Reilly SS, Luo G, Briggs DEG, Summons RE. Prospects for Sterane Preservation in Sponge Fossils from Museum Collections and the Utility of Sponge Biomarkers for Molecular Clocks. BULLETIN OF THE PEABODY MUSEUM OF NATURAL HISTORY 2016. [DOI: 10.3374/014.057.0208] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
179
|
|
180
|
Affiliation(s)
- Gonzalo Giribet
- Museum of Comparative Zoology & Department of Organismic and Evolutionary Biology Harvard University 26 Oxford Street Cambridge MA 02138 USA
- Department of Life Sciences The Natural History Museum Cromwell Road London SW7 5BD UK
| |
Collapse
|
181
|
Lavrov DV, Pett W. Animal Mitochondrial DNA as We Do Not Know It: mt-Genome Organization and Evolution in Nonbilaterian Lineages. Genome Biol Evol 2016; 8:2896-2913. [PMID: 27557826 PMCID: PMC5633667 DOI: 10.1093/gbe/evw195] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2016] [Indexed: 12/11/2022] Open
Abstract
Animal mitochondrial DNA (mtDNA) is commonly described as a small, circular molecule that is conserved in size, gene content, and organization. Data collected in the last decade have challenged this view by revealing considerable diversity in animal mitochondrial genome organization. Much of this diversity has been found in nonbilaterian animals (phyla Cnidaria, Ctenophora, Placozoa, and Porifera), which, from a phylogenetic perspective, form the main branches of the animal tree along with Bilateria. Within these groups, mt-genomes are characterized by varying numbers of both linear and circular chromosomes, extra genes (e.g. atp9, polB, tatC), large variation in the number of encoded mitochondrial transfer RNAs (tRNAs) (0-25), at least seven different genetic codes, presence/absence of introns, tRNA and mRNA editing, fragmented ribosomal RNA genes, translational frameshifting, highly variable substitution rates, and a large range of genome sizes. This newly discovered diversity allows a better understanding of the evolutionary plasticity and conservation of animal mtDNA and provides insights into the molecular and evolutionary mechanisms shaping mitochondrial genomes.
Collapse
Affiliation(s)
- Dennis V Lavrov
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University
| | - Walker Pett
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University Laboratoire de Biométrie et Biologie Évolutive, Université Lyon 1, Villeurbanne, France
| |
Collapse
|
182
|
Mauri M, Kirchner M, Aharoni R, Ciolli Mattioli C, van den Bruck D, Gutkovitch N, Modepalli V, Selbach M, Moran Y, Chekulaeva M. Conservation of miRNA-mediated silencing mechanisms across 600 million years of animal evolution. Nucleic Acids Res 2016; 45:938-950. [PMID: 27604873 PMCID: PMC5314787 DOI: 10.1093/nar/gkw792] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/22/2016] [Accepted: 08/28/2016] [Indexed: 12/11/2022] Open
Abstract
Our current knowledge about the mechanisms of miRNA silencing is restricted to few lineages such as vertebrates, arthropods, nematodes and land plants. miRNA-mediated silencing in bilaterian animals is dependent on the proteins of the GW182 family. Here, we dissect the function of GW182 protein in the cnidarian Nematostella, separated by 600 million years from other Metazoa. Using cultured human cells, we show that Nematostella GW182 recruits the CCR4-NOT deadenylation complexes via its tryptophan-containing motifs, thereby inhibiting translation and promoting mRNA decay. Further, similarly to bilaterians, GW182 in Nematostella is recruited to the miRNA repression complex via interaction with Argonaute proteins, and functions downstream to repress mRNA. Thus, our work suggests that this mechanism of miRNA-mediated silencing was already active in the last common ancestor of Cnidaria and Bilateria.
Collapse
Affiliation(s)
- Marta Mauri
- Non-coding RNAs and mechanisms of cytoplasmic gene regulation, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | - Marieluise Kirchner
- Proteome dynamics, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | - Reuven Aharoni
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91905, Israel
| | - Camilla Ciolli Mattioli
- Non-coding RNAs and mechanisms of cytoplasmic gene regulation, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | - David van den Bruck
- Non-coding RNAs and mechanisms of cytoplasmic gene regulation, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | - Nadya Gutkovitch
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91905, Israel
| | - Vengamanaidu Modepalli
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91905, Israel
| | - Matthias Selbach
- Proteome dynamics, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | - Yehu Moran
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91905, Israel
| | - Marina Chekulaeva
- Non-coding RNAs and mechanisms of cytoplasmic gene regulation, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| |
Collapse
|
183
|
Shen XX, Salichos L, Rokas A. A Genome-Scale Investigation of How Sequence, Function, and Tree-Based Gene Properties Influence Phylogenetic Inference. Genome Biol Evol 2016; 8:2565-80. [PMID: 27492233 PMCID: PMC5010910 DOI: 10.1093/gbe/evw179] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2016] [Indexed: 12/13/2022] Open
Abstract
Molecular phylogenetic inference is inherently dependent on choices in both methodology and data. Many insightful studies have shown how choices in methodology, such as the model of sequence evolution or optimality criterion used, can strongly influence inference. In contrast, much less is known about the impact of choices in the properties of the data, typically genes, on phylogenetic inference. We investigated the relationships between 52 gene properties (24 sequence-based, 19 function-based, and 9 tree-based) with each other and with three measures of phylogenetic signal in two assembled data sets of 2,832 yeast and 2,002 mammalian genes. We found that most gene properties, such as evolutionary rate (measured through the percent average of pairwise identity across taxa) and total tree length, were highly correlated with each other. Similarly, several gene properties, such as gene alignment length, Guanine-Cytosine content, and the proportion of tree distance on internal branches divided by relative composition variability (treeness/RCV), were strongly correlated with phylogenetic signal. Analysis of partial correlations between gene properties and phylogenetic signal in which gene evolutionary rate and alignment length were simultaneously controlled, showed similar patterns of correlations, albeit weaker in strength. Examination of the relative importance of each gene property on phylogenetic signal identified gene alignment length, alongside with number of parsimony-informative sites and variable sites, as the most important predictors. Interestingly, the subsets of gene properties that optimally predicted phylogenetic signal differed considerably across our three phylogenetic measures and two data sets; however, gene alignment length and RCV were consistently included as predictors of all three phylogenetic measures in both yeasts and mammals. These results suggest that a handful of sequence-based gene properties are reliable predictors of phylogenetic signal and could be useful in guiding the choice of phylogenetic markers.
Collapse
Affiliation(s)
- Xing-Xing Shen
- Department of Biological Sciences, Vanderbilt University
| | - Leonidas Salichos
- Department of Biological Sciences, Vanderbilt University Department of Molecular Biophysics and Biochemistry, Yale University
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University
| |
Collapse
|
184
|
Ryan JF, Schnitzler CE, Tamm SL. Meeting report of Ctenopalooza: the first international meeting of ctenophorologists. EvoDevo 2016. [PMCID: PMC4997693 DOI: 10.1186/s13227-016-0057-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Here we present a report on Ctenopalooza: A meeting of ctenophorologists held at the Whitney Laboratory for Marine Bioscience in St. Augustine, FL, USA, on March 14–15, 2016. In this report, we provide a summary of each of the sessions that occurred during this two-day meeting, which touched on most of the relevant areas of ctenophore biology. The report includes some major themes regarding the future of ctenophore research that emerged during Ctenopalooza. More information can be found at the meeting Web site: http://ctenopalooza.whitney.ufl.edu.
Collapse
|
185
|
Newman SA. 'Biogeneric' developmental processes: drivers of major transitions in animal evolution. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150443. [PMID: 27431521 PMCID: PMC4958937 DOI: 10.1098/rstb.2015.0443] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2016] [Indexed: 02/07/2023] Open
Abstract
Using three examples drawn from animal systems, I advance the hypothesis that major transitions in multicellular evolution often involved the constitution of new cell-based materials with unprecedented morphogenetic capabilities. I term the materials and formative processes that arise when highly evolved cells are incorporated into mesoscale matter 'biogeneric', to reflect their commonality with, and distinctiveness from, the organizational properties of non-living materials. The first transition arose by the innovation of classical cell-adhesive cadherins with transmembrane linkage to the cytoskeleton and the appearance of the morphogen Wnt, transforming some ancestral unicellular holozoans into 'liquid tissues', and thereby originating the metazoans. The second transition involved the new capabilities, within a basal metazoan population, of producing a mechanically stable basal lamina, and of planar cell polarization. This gave rise to the eumetazoans, initially diploblastic (two-layered) forms, and then with the addition of extracellular matrices promoting epithelial-mesenchymal transformation, three-layered triploblasts. The last example is the fin-to-limb transition. Here, the components of a molecular network that promoted the development of species-idiosyncratic endoskeletal elements in gnathostome ancestors are proposed to have evolved to a dynamical regime in which they constituted a Turing-type reaction-diffusion system capable of organizing the stereotypical arrays of elements of lobe-finned fish and tetrapods. The contrasting implications of the biogeneric materials-based and neo-Darwinian perspectives for understanding major evolutionary transitions are discussed.This article is part of the themed issue 'The major synthetic evolutionary transitions'.
Collapse
Affiliation(s)
- Stuart A Newman
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA
| |
Collapse
|
186
|
Copley RR. The Unicellular Ancestry of Groucho-Mediated Repression and the Origins of Metazoan Transcription Factors. Genome Biol Evol 2016; 8:1859-67. [PMID: 27189982 PMCID: PMC4943189 DOI: 10.1093/gbe/evw118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Groucho is a co-repressor that interacts with many transcription factors playing a crucial role in animal development. The evolutionary origins of Groucho are not clear. It is generally regarded as being a distinct animal-specific protein, although with similarities to the yeast Tup-like proteins. Here, it is shown that Groucho has true orthologs in unicellular relatives of animals. Based on their phylogenetic distribution, and an analysis of ligand-binding residues, these genes are unlikely to be orthologs of the fungal Tup-like genes. By identifying conserved candidate Groucho interaction motifs (GIMs) in nonmetazoan transcription factors, it is demonstrated that the details of molecular interactions between Groucho and transcription factors are likely to have been established prior to the origin of animals, but that the association of GIMs with many transcription factor types can be regarded as a metazoan innovation.
Collapse
Affiliation(s)
- Richard R Copley
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), 181 chemin du Lazaret, 06230 Villefranche-sur-mer, France
| |
Collapse
|
187
|
Ctenophores: an evolutionary-developmental perspective. Curr Opin Genet Dev 2016; 39:85-92. [PMID: 27351593 DOI: 10.1016/j.gde.2016.05.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 05/04/2016] [Accepted: 05/30/2016] [Indexed: 11/22/2022]
Abstract
Ctenophores are non-bilaterian metazoans of uncertain phylogenetic position, some recent studies placing them as sister-group to all other animals whereas others suggest this placement is artefactual and ctenophores are more closely allied with cnidarians and bilaterians, with which they share nerve cells, muscles and gut. Available information about developmental genes and their expression and function in ctenophores is reviewed. These data not only unveil some conserved aspects of molecular developmental mechanisms with other basal metazoan lineages, but also can be expected to enlighten the genomic and molecular bases of the evolution of ctenophore-specific traits, including their unique embryonic development, complex anatomy and high cell type diversity.
Collapse
|
188
|
Adamska M. Sponges as models to study emergence of complex animals. Curr Opin Genet Dev 2016; 39:21-28. [PMID: 27318691 DOI: 10.1016/j.gde.2016.05.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/20/2016] [Accepted: 05/30/2016] [Indexed: 02/05/2023]
Abstract
The emergence of complex animal life forms remains poorly understood despite substantial interest and research in this area. To be informative, the ideal models to study transitions from single-cell organisms to the first animals and then to mammalian-level complexity should be phylogenetically strategically placed and retain ancestral characters. Sponges (Porifera) are likely to be the earliest branching animal phylum. When analysed from morphological, genomic and developmental perspectives, sponges appear to combine features of single-cell eukaryotic organisms and the complex multicellular animals (Eumetazoa). Intriguingly, homologues of components of the eumetazoan regulatory networks specifying the endoderm, the germ-cells and stem cells and (neuro) sensory cells are expressed in sponge choanocytes, archaeocytes and larval sensory cells. Studies using sponges as model systems are already bringing insights into animal evolution, and have opened avenues to further research benefitting from the recent spectacular expansion of genomic technologies.
Collapse
Affiliation(s)
- Maja Adamska
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia.
| |
Collapse
|
189
|
|
190
|
Abstract
The recent increase in genomic data is revealing an unexpected perspective of gene loss as a pervasive source of genetic variation that can cause adaptive phenotypic diversity. This novel perspective of gene loss is raising new fundamental questions. How relevant has gene loss been in the divergence of phyla? How do genes change from being essential to dispensable and finally to being lost? Is gene loss mostly neutral, or can it be an effective way of adaptation? These questions are addressed, and insights are discussed from genomic studies of gene loss in populations and their relevance in evolutionary biology and biomedicine.
Collapse
|
191
|
Sasson DA, Ryan JF. The sex lives of ctenophores: the influence of light, body size, and self-fertilization on the reproductive output of the sea walnut, Mnemiopsis leidyi. PeerJ 2016; 4:e1846. [PMID: 27042395 PMCID: PMC4811168 DOI: 10.7717/peerj.1846] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/03/2016] [Indexed: 12/31/2022] Open
Abstract
Ctenophores (comb jellies) are emerging as important animals for investigating fundamental questions across numerous branches of biology (e.g., evodevo, neuroscience and biogeography). A few ctenophore species including, most notably, Mnemiopsis leidyi, are considered as invasive species, adding to the significance of studying ctenophore ecology. Despite the growing interest in ctenophore biology, relatively little is known about their reproduction. Like most ctenophores, M. leidyi is a simultaneous hermaphrodite capable of self-fertilization. In this study, we assess the influence of light on spawning, the effect of body size on spawning likelihood and reproductive output, and the cost of self-fertilization on egg viability in M. leidyi. Our results suggest that M. leidyi spawning is more strongly influenced by circadian rhythms than specific light cues and that body size significantly impacts spawning and reproductive output. Mnemiopsis leidyi adults that spawned alone produced a lower percentage of viable embryos versus those that spawned in pairs, suggesting that self-fertilization may be costly in this species. These results provide insight into the reproductive ecology of M. leidyi and provide a fundamental resource for researchers working with them in the laboratory.
Collapse
Affiliation(s)
- Daniel A Sasson
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, Florida, United States of America; Department of Biology, University of Florida, Gainesville, Florida, United States of America
| | - Joseph F Ryan
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, Florida, United States of America; Department of Biology, University of Florida, Gainesville, Florida, United States of America
| |
Collapse
|
192
|
Sogabe S, Nakanishi N, Degnan BM. The ontogeny of choanocyte chambers during metamorphosis in the demosponge Amphimedon queenslandica. EvoDevo 2016; 7:6. [PMID: 26958337 PMCID: PMC4782300 DOI: 10.1186/s13227-016-0042-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 02/10/2016] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The aquiferous body plan of poriferans revolves around internal chambers comprised of choanocytes, a cell type structurally similar to choanoflagellates. These choanocyte chambers perform a range of physiological and developmental functions, including the capture of food and the generation of stem cells. Despite the increasing interest for choanocytes as sponge stem cells, there is limited knowledge on the development of choanocyte chambers. Using a combination of cell lineage tracing, antibody staining and EdU labeling, here we examine the development of choanocytes and the chambers they comprise during metamorphosis in the marine demosponge Amphimedon queenslandica. RESULTS Lineage-tracing experiments show that larval epithelial cells transform into mesenchymal pluripotent stem cells, resembling archeocytes, within 24 h of initiating metamorphosis. By 36 h, some of these labeled archeocyte-like cells have differentiated into choanocytes that will form the first postlarval choanocyte chambers. Non-labeled cells also contribute to these primary choanocyte chambers, consistent with these chambers being a chimera of multiple transdifferentiated larval cell types and not the proliferation of a single choanocyte precursor. Moreover, cell proliferation assays demonstrate that, following the initial formation of choanocyte chambers, chambers grow at least partially by the proliferation of choanocytes within the chamber, although recruitment of individual cells into established chambers also appears to occur. EdU labeling of postlarvae and juveniles reveals that choanocyte chambers are the primary location of cell proliferation during metamorphosis. CONCLUSION Our results show that multiple larval cell lineages typically contribute to formation of individual choanocyte chambers at metamorphosis, contrary to previous reports in other species that show sponge choanocyte chambers form clonally. Choanocytes in postlarval and juvenile A. queenslandica chambers can also divide, with choanocyte chambers being the primary location of cell proliferation. Interestingly, the level of cell proliferation varies greatly between chambers and appears to be contingent on the size, location and developmental state of the chamber. Small chambers on the periphery of the body tend to possess more dividing cells. As choanocytes can also dedifferentiate into archeocyte-like cells, cell proliferation in chambers may not only contribute to chamber growth and self-renewal but also increase the number of pluripotent archeocytes.
Collapse
Affiliation(s)
- Shunsuke Sogabe
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
| | - Nagayasu Nakanishi
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
| | - Bernard M Degnan
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
| |
Collapse
|
193
|
Schenkelaars Q, Quintero O, Hall C, Fierro-Constain L, Renard E, Borchiellini C, Hill AL. ROCK inhibition abolishes the establishment of the aquiferous system in Ephydatia muelleri (Porifera, Demospongiae). Dev Biol 2016; 412:298-310. [PMID: 26944094 DOI: 10.1016/j.ydbio.2016.02.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Revised: 02/16/2016] [Accepted: 02/26/2016] [Indexed: 01/16/2023]
Abstract
The Rho associated coiled-coil protein kinase (ROCK) plays crucial roles in development across bilaterian animals. The fact that the Rho/Rock pathway is required to initiate epithelial morphogenesis and thus to establish body plans in bilaterians makes this conserved signaling pathway key for studying the molecular mechanisms that may control early development of basally branching metazoans. The purpose of this study was to evaluate whether or not the main components of this signaling pathway exist in sponges, and if present, to investigate the possible role of the regulatory network in an early branching non-bilaterian species by evaluating ROCK function during Ephydatia muelleri development. Molecular phylogenetic analyses and protein domain predictions revealed the existence of Rho/Rock components in all studied poriferan lineages. Binding assays revealed that both Y-27632 and GSK429286A are capable of inhibiting Em-ROCK activity in vitro. Treatment with both drugs leads to impairment of growth and formation of the basal pinacoderm layer in the developing sponge. Furthermore, inhibition of Em-Rock prevents the establishment of a functional aquiferous system, including the absence of an osculum. In contrast, no effect of ROCK inhibition was observed in juvenile sponges that already possess a fully developed and functional aquiferous system. Thus, the Rho/Rock pathway appears to be essential for the proper development of the freshwater sponge, and may play a role in various cell behaviors (e.g. cell proliferation, cell adhesion and cell motility). Taken together, these data are consistent with an ancestral function of Rho/Rock signaling in playing roles in early developmental processes and may provide a new framework to study the interaction between Wnt signaling and the Rho/Rock pathway.
Collapse
Affiliation(s)
- Quentin Schenkelaars
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE) - UMR CNRS 7263- IRD 237 - UAPV, Aix-Marseille Université, Marseille, France; Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (IGe3), Faculty of Sciences, University of Geneva, Switzerland.
| | - Omar Quintero
- Department of Biology, University of Richmond, Richmond, VA 23173, USA
| | - Chelsea Hall
- Department of Biology, University of Richmond, Richmond, VA 23173, USA
| | - Laura Fierro-Constain
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE) - UMR CNRS 7263- IRD 237 - UAPV, Aix-Marseille Université, Marseille, France
| | - Emmanuelle Renard
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE) - UMR CNRS 7263- IRD 237 - UAPV, Aix-Marseille Université, Marseille, France
| | - Carole Borchiellini
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE) - UMR CNRS 7263- IRD 237 - UAPV, Aix-Marseille Université, Marseille, France
| | - April L Hill
- Department of Biology, University of Richmond, Richmond, VA 23173, USA.
| |
Collapse
|
194
|
Coste A, Jager M, Chambon JP, Manuel M. Comparative study of Hippo pathway genes in cellular conveyor belts of a ctenophore and a cnidarian. EvoDevo 2016; 7:4. [PMID: 26900447 PMCID: PMC4761220 DOI: 10.1186/s13227-016-0041-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 02/10/2016] [Indexed: 11/14/2022] Open
Abstract
Background The Hippo pathway regulates growth rate and organ size in fly and mouse, notably through control of cell proliferation. Molecular interactions at the heart of this pathway are known to have originated in the unicellular ancestry of metazoans. They notably involve a cascade of phosphorylations triggered by the kinase Hippo, with subsequent nuclear to cytoplasmic shift of Yorkie localisation, preventing its binding to the transcription factor Scalloped, thereby silencing proliferation genes. There are few comparative expression data of Hippo pathway genes in non-model animal species and notably none in non-bilaterian phyla. Results All core Hippo pathway genes could be retrieved from the ctenophore Pleurobrachia pileus and the hydrozoan cnidarian Clytia hemisphaerica, with the important exception of Yorkie in ctenophore. Expression study of the Hippo, Salvador and Scalloped genes in tentacle “cellular conveyor belts” of these two organisms revealed striking differences. In P. pileus, their transcripts were detected in areas where undifferentiated progenitors intensely proliferate and where expression of cyclins B and D was also seen. In C. hemisphaerica, these three genes and Yorkie are expressed not only in the proliferating but also in the differentiation zone of the tentacle bulb and in mature tentacle cells. However, using an antibody designed against the C. hemiphaerica Yorkie protein, we show in two distinct cell lineages of the medusa that Yorkie localisation is predominantly nuclear in areas of active cell proliferation and mainly cytoplasmic elsewhere. Conclusions This is the first evidence of nucleocytoplasmic Yorkie shift in association with the arrest of cell proliferation in a cnidarian, strongly evoking the cell division-promoting role of this protein and its inhibition by the activated Hippo pathway in bilaterian models. Our results furthermore highlight important differences in terms of deployment and regulation of Hippo pathway genes between cnidarians and ctenophores. Electronic supplementary material The online version of this article (doi:10.1186/s13227-016-0041-y) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Alicia Coste
- Sorbonne Universités, Université Pierre et Marie Curie (UPMC), Institut de Biologie Paris-Seine (IBPS) CNRS, UMR 7138 Evolution Paris-Seine, Case 05, 7 quai St Bernard, 75005 Paris, France
| | - Muriel Jager
- Sorbonne Universités, Université Pierre et Marie Curie (UPMC), Institut de Biologie Paris-Seine (IBPS) CNRS, UMR 7138 Evolution Paris-Seine, Case 05, 7 quai St Bernard, 75005 Paris, France
| | - Jean-Philippe Chambon
- Sorbonne Universités, Université Pierre et Marie Curie (UPMC), Institut de Biologie Paris-Seine (IBPS) CNRS, UMR 7138 Evolution Paris-Seine, Case 05, 7 quai St Bernard, 75005 Paris, France
| | - Michaël Manuel
- Sorbonne Universités, Université Pierre et Marie Curie (UPMC), Institut de Biologie Paris-Seine (IBPS) CNRS, UMR 7138 Evolution Paris-Seine, Case 05, 7 quai St Bernard, 75005 Paris, France
| |
Collapse
|
195
|
|
196
|
Reply to Halanych et al.: Ctenophore misplacement is corroborated by independent datasets. Proc Natl Acad Sci U S A 2016; 113:E948-9. [PMID: 26862176 DOI: 10.1073/pnas.1525718113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
197
|
Schierwater B, Holland PWH, Miller DJ, Stadler PF, Wiegmann BM, Wörheide G, Wray GA, DeSalle R. Never Ending Analysis of a Century Old Evolutionary Debate: “Unringing” the Urmetazoon Bell. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
198
|
|
199
|
|
200
|
Liebeskind BJ, Hillis DM, Zakon HH, Hofmann HA. Complex Homology and the Evolution of Nervous Systems. Trends Ecol Evol 2015; 31:127-135. [PMID: 26746806 DOI: 10.1016/j.tree.2015.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 12/01/2015] [Accepted: 12/02/2015] [Indexed: 02/07/2023]
Abstract
We examine the complex evolution of animal nervous systems and discuss the ramifications of this complexity for inferring the nature of early animals. Although reconstructing the origins of nervous systems remains a central challenge in biology, and the phenotypic complexity of early animals remains controversial, a compelling picture is emerging. We now know that the nervous system and other key animal innovations contain a large degree of homoplasy, at least on the molecular level. Conflicting hypotheses about early nervous system evolution are due primarily to differences in the interpretation of this homoplasy. We highlight the need for explicit discussion of assumptions and discuss the limitations of current approaches for inferring ancient phenotypic states.
Collapse
Affiliation(s)
- Benjamin J Liebeskind
- Center for Systems and Synthetic Biology, University of Texas, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712.
| | - David M Hillis
- Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712; Department of Integrative Biology, University of Texas, Austin, TX 78712, USA
| | - Harold H Zakon
- Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712; Department of Integrative Biology, University of Texas, Austin, TX 78712, USA; Department of Neuroscience, University of Texas, Austin, TX 78712, USA; Institute for Neuroscience, University of Texas, Austin, TX 78712, USA; Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Hans A Hofmann
- Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712; Department of Integrative Biology, University of Texas, Austin, TX 78712, USA; Department of Neuroscience, University of Texas, Austin, TX 78712, USA; Institute for Neuroscience, University of Texas, Austin, TX 78712, USA
| |
Collapse
|