Introduction to the 2024 Chordate Origins, Evolution and Development SICB Symposium.

The evolution of the distinct chordate body plan has intrigued scientists for over a hundred and seventy years. Modern genomics and transcriptomics have allowed the elucidation of the Developmental Gene Regulatory Networks (GRNs) underlying the developmental programs for particular tissues and body axes in invertebrates and vertebrates. This has been most revealing in the Deuterostomia, the superphylum in which chordates evolved.

Deuterostome Ancestors and Chordate Origins.

The Deuterostomia are a monophyletic group, consisting of the Ambulacraria, with two phyla, Hemichordata and Echinodermata, and the phylum Chordata, containing the subphyla Cephalochordata (lancelets or Amphioxus), Tunicata (Urochordata), and Vertebrata. Hemichordates and echinoderms are sister groups and are critical for understanding the deuterostome ancestor and the origin and evolution of the chordates within the deuterostomes. Enteropneusta, worm-like hemichordates, share many chordate features as adults, including a post-anal tail, gill slits, and a central nervous system (CNS) that deploys similar developmental genetic regulatory networks (GRNs).

, a Maternal and Zygotic SHARK Family Tyrosine Kinase Gene, Is Disrupted in , a Tailless Ascidian.

AbstractWe describe the cloning and expression of a nonreceptor tyrosine kinase, (), a () gene, identified in a subtractive screen for maternal ascidian cDNAs in , an ascidian species with a tadpole larva. The gene encodes a 4-kb mRNA expressed in gonads, eggs, and embryos in the tailed but is not detected in eggs or embryos of the closely related tailless species . There is a large insertion in in the genome, as shown by transcriptome and genome analyses, resulting in it becoming a pseudogene.

Standardizing data reporting in the research community to enhance the utility of open data for SARS-CoV-2 wastewater surveillance.

SARS-CoV-2 RNA detection in wastewater is being rapidly developed and adopted as a public health monitoring tool worldwide. With wastewater surveillance programs being implemented across many different scales and by many different stakeholders, it is critical that data collected and shared are accompanied by an appropriate minimal amount of metainformation to enable meaningful interpretation and use of this new information source and intercomparison across datasets. While some databases are being developed for specific surveillance programs locally, regionally, nationally, and internationally, common globally-adopted data standards have not yet been established within the research community.

An Introduction to an Evolutionary Tail: EvoDevo, Structure, and Function of Post-Anal Appendages.

Although tails are common and versatile appendages that contribute to evolutionary success of animals in a broad range of ways, a scientific synthesis on the topic is yet to be initiated. For our Society for Integrative and Comparative Biology (SICB) symposium, we brought together researchers from different areas of expertise (e.g.

Future Tail Tales: A Forward-Looking, Integrative Perspective on Tail Research.

Synopsis Tails are a defining characteristic of chordates and show enormous diversity in function and shape. Although chordate tails share a common evolutionary and genetic-developmental origin, tails are extremely versatile in morphology and function. For example, tails can be short or long, thin or thick, and feathered or spiked, and they can be used for propulsion, communication, or balancing, and they mediate in predator-prey outcomes.

The Degenerate Tale of Ascidian Tails.

Ascidians are invertebrate chordates, with swimming chordate tadpole larvae that have distinct heads and tails. The head contains the small brain, sensory organs, including the ocellus (light) and otolith (gravity) and the presumptive endoderm, while the tail has a notochord surrounded by muscle cells and a dorsal nerve cord. One of the chordate features is a post-anal tail.

Transitional chordates and vertebrate origins: Tunicates.

The Origin of Chordates has fascinated scientists from the time of Charles Darwin's publication "Descent of Man" in 1871. For over 100 years, it was accepted that chordates evolved from tunicates, our sessile invertebrate sister group. However, genomic and embryonic analyses have shown that lancelets have a body plan and genome much more like vertebrates than do tunicates.

A cis-regulatory change underlying the motor neuron-specific loss of Ebf expression in immotile tunicate larvae.

Many species in the tunicate family Molgulidae have independently lost their swimming larval form and instead develop as tailless, immotile larvae. These larvae do not develop structures that are essential for swimming such as the notochord, otolith, and tail muscles. However, little is known about neural development in these nonswimming larvae.

High Time for Hair Cells: An Introduction to the Symposium on Sensory Hair Cells.

Sensory hair cells are highly specialized cells that form the basis for our senses of hearing, orientation to gravity, and perception of linear acceleration (head translation in space) and angular acceleration (head rotation). In many species of fish and aquatic amphibians, hair cells mediate perception of water movement through the lateral line system, and electroreceptors derived from hair cell precursors mediate electric field detection. In tunicates, cells of the mechanosensory coronal organ on the incurrent siphon meet the structural, functional, and developmental criteria to be described as hair cells, and they function to deflect large particles from entering the animal.

Evaluation of Legiolert for Quantification of Legionella pneumophila from Non-potable Water.

Legiolert® is a new culture method for quantification of Legionella pneumophila, which is the primary species associated with Legionnaires' disease. The test is based on a most probable number approach, and differs significantly from traditional culture methods by providing results at 7 days, rapid sample preparation and analysis, and objective interpretation of test results. In this study, we compared the performance of Legiolert with the U.

Getting a Head with Ptychodera flava Larval Regeneration.

Severe injury to the central nervous system of chordates often results in permanent and irreversible mental and physical challenges. While some chordates are able to repair and/or regenerate portions of their nervous system, no chordate has been shown to be able to regenerate all regions of its central nervous system after catastrophic injury or amputation. Some hemichordates, on the other hand, are able to efficiently regenerate all neural structures, including their dorsal, hollow neural tube after complete ablation.

Phylogenomics offers resolution of major tunicate relationships.

Tunicata, a diverse clade of approximately 3000 described species of marine, filter-feeding chordates, is of great interest to researchers because tunicates are the closest living relatives of vertebrates and they facilitate comparative studies of our own biology. The group also includes numerous invasive species that cause considerable economic damage and some species of tunicates are edible. Despite their diversity and importance, relationships among major lineages of Tunicata are not completely resolved.

ANISEED 2017: extending the integrated ascidian database to the exploration and evolutionary comparison of genome-scale datasets.

ANISEED (www.aniseed.cnrs.

Evolutionary loss of melanogenesis in the tunicate .

Background: Analyzing close species with diverse developmental modes is instrumental for investigating the evolutionary significance of physiological, anatomical and behavioral features at a molecular level. Many examples of trait loss are known in metazoan populations living in dark environments. Tunicates are the closest living relatives of vertebrates and typically present a lifecycle with distinct motile larval and sessile adult stages.

Head regeneration in hemichordates is not a strict recapitulation of development.

Background: Head or anterior body part regeneration is commonly associated with protostome, but not deuterostome invertebrates. However, it has been shown that the solitary hemichordate Ptychodera flava possesses the remarkable capacity to regenerate their entire nervous system, including their dorsal neural tube and their anterior head-like structure, or proboscis. Hemichordates, also known as acorn worms, are marine invertebrate deuterostomes that have retained chordate traits that were likely present in the deuterostome ancestor, placing these animals in a vital position to study regeneration and chordate evolution.

The Presence of a Functionally Tripartite Through-Gut in Ctenophora Has Implications for Metazoan Character Trait Evolution.

The current paradigm of gut evolution assumes that non-bilaterian metazoan lineages either lack a gut (Porifera and Placozoa) or have a sac-like gut (Ctenophora and Cnidaria) and that a through-gut originated within Bilateria [1-8]. An important group for understanding early metazoan evolution is Ctenophora (comb jellies), which diverged very early from the animal stem lineage [9-13]. The perception that ctenophores possess a sac-like blind gut with only one major opening remains a commonly held misconception [4, 5, 7, 14, 15].

The Global Diversity of Hemichordata.

Phylum Hemichordata, composed of worm-like Enteropneusta and colonial Pterobranchia, has been reported to only contain about 100 species. However, recent studies of hemichordate phylogeny and taxonomy suggest the species number has been largely underestimated. One issue is that species must be described by experts, and historically few taxonomists have studied this group of marine invertebrates.

A revisited phylogeography of Nautilus pompilius.

The cephalopod genus Nautilus is considered a "living fossil" with a contested number of extant and extinct species, and a benthic lifestyle that limits movement of animals between isolated seamounts and landmasses in the Indo-Pacific. Nautiluses are fished for their shells, most heavily in the Philippines, and these fisheries have little monitoring or regulation. Here, we evaluate the hypothesis that multiple species of Nautilus (e.

Simulating social-ecological systems: the Island Digital Ecosystem Avatars (IDEA) consortium.

Systems biology promises to revolutionize medicine, yet human wellbeing is also inherently linked to healthy societies and environments (sustainability). The IDEA Consortium is a systems ecology open science initiative to conduct the basic scientific research needed to build use-oriented simulations (avatars) of entire social-ecological systems. Islands are the most scientifically tractable places for these studies and we begin with one of the best known: Moorea, French Polynesia.

ANISEED 2015: a digital framework for the comparative developmental biology of ascidians.

Ascidians belong to the tunicates, the sister group of vertebrates and are recognized model organisms in the field of embryonic development, regeneration and stem cells. ANISEED is the main information system in the field of ascidian developmental biology. This article reports the development of the system since its initial publication in 2010.

Biogeography of Phallusia nigra: is it really black and white?

Ascidians (Chordata, Tunicata) are an important group for the study of invasive species biology due to rapid generation times, potential for biofouling, and role as filter feeders in an ecosystem. Phallusia nigra is a putative cosmopolitan ascidian that has been described as introduced or invasive in a number of regions in the Indo-Pacific Ocean (India, Japan, and Hawaii) and in the Mediterranean. The taxonomic description of P.