Mammals exhibit a remarkable variety of phenotypes and comparative studies using novel model species are needed to uncover the evolutionary developmental mechanisms generating this diversity. Here, we undertak...
Authors: Sophie A Montandon, Athanasia C Tzika, António F Martins, Bastien Chopard and Michel C Milinkovitch
Annual killifishes inhabit temporary ponds and their embryos survive the dry season encased in the mud by entering diapause, a process that arrests embryonic development during hostile conditions. Annual killi...
Authors: Luca Dolfi, Roberto Ripa and Alessandro Cellerino
During development, juvenile nematodes undergo four molts. Although the number of molts appears to be constant within the Nematoda, the timing of the first molt can occur either before or after hatching. A pre...
Cellular differentiation is a critical process during development of multicellular animals that must be tightly controlled in order to avoid precocious differentiation or failed generation of differentiated ce...
The Hes superfamily or Hes/Hey-related genes encompass a variety of metazoan-specific bHLH genes, with somewhat fuzzy phylogenetic relationships. Hes superfamily members are involved in a variety of major develop...
Authors: Eve Gazave, Aurélien Guillou and Guillaume Balavoine
The teleost Astyanax mexicanus is a single species consisting of eyed surface-dwelling (surface fish) and blind cave-dwelling (cavefish) morphs. Cavefish eyes are lost through apoptosis of the lens, which in turn...
Authors: Li Ma, Amy Parkhurst and William R Jeffery
Disentangling evolutionary shifts in developmental timing (heterochony) is dependent upon accurate estimates of ancestral patterns. However, many classic assessments of heterochronic patterns predate robust ph...
Authors: Ronald M Bonett, Michael A Steffen and Grant A Robison
The primary hormone of the vertebrate pineal gland, melatonin, has been identified broadly throughout the eukaryotes. While the role for melatonin in cyclic behavior via interactions with the circadian clock h...
Authors: Rafael Peres, Adam M Reitzel, Yale Passamaneck, Solange Castro Afeche, José Cipolla-Neto, Antonio Carlos Marques and Mark Q Martindale
A particularly critical event in avian evolution was the transition from long- to short-tailed birds. Primitive bird tails underwent significant alteration, most notably reduction of the number of caudal verte...
Authors: Dana J Rashid, Susan C Chapman, Hans CE Larsson, Chris L Organ, Anne-Gaelle Bebin, Christa S Merzdorf, Roger Bradley and John R Horner
Segmentation is a feature of the body plans of a number of diverse animal groupings, including the annelids, arthropods and chordates. However, it has been unclear whether or not these different manifestations...
Authors: Anthony Graham, Thomas Butts, Andrew Lumsden and Clemens Kiecker
The Pax-Six-Eya-Dach network (PSEDN) is involved in a variety of developmental processes, including well documented roles in determination of sensory organs and morphogenesis in bilaterian animals. Expression of ...
Authors: Sofia AV Fortunato, Sven Leininger and Maja Adamska
The Hox gene cluster ranks among the greatest of biological discoveries of the past 30 years. Morphogenetic patterning genes are remarkable for the systems they regulate during major ontogenetic events, and fo...
The canals of the mechanosensory lateral line system are components of the dermatocranium, and demonstrate phenotypic variation in bony fishes. Widened lateral line canals evolved convergently in a limited num...
The bHLH-PAS transcription factors are found in both protostomes and deuterostomes. They are involved in many developmental and physiological processes, including regional differentiation of the central nervou...
Convergent evolution, the repeated evolution of similar phenotypes in independent lineages, provides natural replicates to study mechanisms of evolution. Cases of convergent evolution might have the same under...
Authors: Andrew M Glazer, Phillip A Cleves, Priscilla A Erickson, Angela Y Lam and Craig T Miller
Germline specification in some animals is driven by the maternally inherited germ plasm during early embryogenesis (inheritance mode), whereas in others it is induced by signals from neighboring cells in mid o...
Authors: Gee-way Lin, Charles E Cook, Toru Miura and Chun-che Chang
The Fox gene family is a large family of transcription factors that arose early in organismal evolution dating back to at least the common ancestor of metazoans and fungi. They are key components of many gene ...
Authors: Jens H Fritzenwanker, John Gerhart, Robert M Freeman Jr and Christopher J Lowe
Diapause is a developmental arrest present in annual killifish, whose eggs are able to survive long periods of desiccation when the temporary ponds they inhabit dry up. Diapause can occur in three different de...
Authors: Irma Varela-Lasheras and Tom JM Van Dooren
The Sox genes, a family of transcription factors characterized by the presence of a high mobility group (HMG) box domain, are among the central groups of developmental regulators in the animal kingdom. They are i...
Authors: Christine E Schnitzler, David K Simmons, Kevin Pang, Mark Q Martindale and Andreas D Baxevanis
The Onychophora are a probable sister group to Arthropoda, one of the most intensively studied animal phyla from a developmental perspective. Pioneering work on the fruit fly Drosophila melanogaster and subsequen...
Authors: Mattias Hogvall, Anna Schönauer, Graham E Budd, Alistair P McGregor, Nico Posnien and Ralf Janssen
For animal cells, ciliation and mitosis appear to be mutually exclusive. While uniciliated cells can resorb their cilium to undergo mitosis, multiciliated cells apparently can never divide again. Nevertheless,...
Authors: April M Bird, George von Dassow and Svetlana A Maslakova
Crustaceans of the genus Daphnia are one of the oldest model organisms in ecotoxicology, ecology and evolutionary biology. The publication of the Daphnia pulex genome has facilitated the development of genetic to...
Authors: Beate Mittmann, Petra Ungerer, Marleen Klann, Angelika Stollewerk and Carsten Wolff
A key early step in embryogenesis is the establishment of the major body axes; the dorsal-ventral (DV) and anterior-posterior (AP) axes. Determination of these axes in some insects requires the function of dif...
Authors: Megan J Wilson, Nathan J Kenny and Peter K Dearden
It is believed that in tapeworms a separate population of undifferentiated cells, the germinative cells, is the only source of cell proliferation throughout the life cycle (similar to the neoblasts of free liv...
Authors: Uriel Koziol, Theresa Rauschendorfer, Luis Zanon Rodríguez, Georg Krohne and Klaus Brehm
Polyclad flatworms offer an excellent system with which to explore the evolution of larval structures and the ecological and developmental mechanisms driving flatworm and marine invertebrate life history evolu...
Heterochronic shifts during ontogeny can result in adaptively important innovations and might be initiated by simple developmental switches. Understanding the nature of these developmental events can provide i...
Authors: Helen M Gunter, Claudia Koppermann and Axel Meyer
While the ecological factors that drive phenotypic radiations are often well understood, less is known about the generative mechanisms that cause the emergence and subsequent diversification of novel features. He...
Authors: Arnaud Martin, Kyle J McCulloch, Nipam H Patel, Adriana D Briscoe, Lawrence E Gilbert and Robert D Reed
Haemocyanin is the respiratory protein of most of the Mollusca. In cephalopods and gastropods at least two distinct isoforms are differentially expressed. However, their physiological purpose is unknown. For t...
Authors: Anne Thonig, Michael Oellermann, Bernhard Lieb and Felix Christopher Mark
Adaptation to a new environment can be facilitated by co-inheritance of a suite of phenotypes that are all advantageous in the new habitat. Although experimental evidence demonstrates that multiple phenotypes ...
Authors: Margaret G Mills, Anna K Greenwood and Catherine L Peichel
An important question in experimental embryology is to understand how the developmental potential responsible for the generation of distinct cell types is spatially segregated over developmental time. Classica...
Authors: Antje HL Fischer, Kevin Pang, Jonathan Q Henry and Mark Q Martindale
The monophyly of Mandibulata - the division of arthropods uniting pancrustaceans and myriapods - is consistent with several morphological characters, such as the presence of sensory appendages called antennae ...
Authors: Prashant P Sharma, Tripti Gupta, Evelyn E Schwager, Ward C Wheeler and Cassandra G Extavour
In Drosophila and many other insects, the Hox genes Ultrabithorax (Ubx) and abdominal-A (abd-A) suppress limb formation on most or all segments of the abdomen. However, a number of basal hexapod lineages retain m...
Comparative studies of developmental processes are one of the main approaches to evolutionary developmental biology (evo-devo). Over recent years, there has been a shift of focus from the comparative study of ...
Authors: Hilde Janssens, Ken Siggens, Damjan Cicin-Sain, Eva Jiménez-Guri, Marco Musy, Michael Akam and Johannes Jaeger
Animals have been described as segmented for more than 2,000 years, yet a precise definition of segmentation remains elusive. Here we give the history of the definition of segmentation, followed by a discussio...
Specification of the germ line is an essential event during the embryonic development of sexually reproducing animals, as germ line cells are uniquely capable of giving rise to the next generation. Animal germ...
In sea urchin larvae the circumesophageal fibers form a prominent muscle system of mesodermal origin. Although the morphology and later development of this muscle system has been well-described, little is know...
Authors: Carmen Andrikou, Edmondo Iovene, Francesca Rizzo, Paola Oliveri and Maria Ina Arnone
Studies on early neurogenesis have had considerable impact on the discussion of the phylogenetic relationships of arthropods, having revealed striking similarities and differences between the major lineages. I...
Authors: Georg Brenneis, Angelika Stollewerk and Gerhard Scholtz
In many bilaterians, asymmetric activation of canonical Wnt (cWnt) signaling at the posterior pole is critical for anterior-posterior (AP) body axis formation. In 16-cell stage sea urchins, nuclearization of β...
Authors: Christine A Byrum and Athula H Wikramanayake
In many insect taxa, wing polymorphism is known to be a consequence of tradeoffs between flight and other life-history traits. The pea aphid Acyrthosiphon pisum exhibits various morphs with or without wings assoc...
Polyclad flatworms are an early branching clade within the rhabditophoran Platyhelminthes. They provide an interesting system with which to explore the evolution of development within Platyhelminthes and among...
Authors: François Lapraz, Kate A Rawlinson, Johannes Girstmair, Bartłomiej Tomiczek, Jürgen Berger, Gáspár Jékely, Maximilian J Telford and Bernhard Egger
The Mexican tetra (Astyanax mexicanus) has emerged as a good animal model to study the constructive and regressive changes associated with living in cave environments, as both the ancestral sighted morph and the ...
Authors: Atukorallaya Devi Sewvandini Atukorala, Christine Hammer, Megan Dufton and Tamara Anne Franz-Odendaal
The question of whether the ancestral bilaterian had a central nervous system (CNS) or a diffuse ectodermal nervous system has been hotly debated. Considerable evidence supports the theory that a CNS evolved j...
Authors: Linda Z Holland, João E Carvalho, Hector Escriva, Vincent Laudet, Michael Schubert, Sebastian M Shimeld and Jr-Kai Yu
Animals inhabiting the darkness of caves are generally blind and de-pigmented, regardless of the phylum they belong to. Survival in this environment is an enormous challenge, the most obvious being to find foo...
In blind cave-dwelling populations of Astyanax mexicanus, several morphological and behavioral shifts occurred during evolution in caves characterized by total and permanent darkness. Previous studies have shown ...
Authors: Jonathan Bibliowicz, Alexandre Alié, Luis Espinasa, Masato Yoshizawa, Maryline Blin, Hélène Hinaux, Laurent Legendre, Stéphane Père and Sylvie Rétaux
Extreme environmental conditions can give rise to extreme adaptations. We document growth, sexual maturation and fecundity in two species of African annual fish inhabiting temporary savanna pools.
Authors: Radim Blažek, Matej Polačik and Martin Reichard
Hox genes encode transcription factors that have an ancestral role in all bilaterian animals in specifying regions along the antero-posterior axis. In arthropods (insects, crustaceans, myriapods and chelicerat...
Most geophilomorph centipedes show intraspecific variability in the number of leg-bearing segments. This intraspecific variability generally has a component that is related to sex, with females having on avera...
A complex life cycle, such as complete metamorphosis, is a key innovation that can promote diversification of species. The evolution of a morphologically distinct larval stage is thought to have enabled insect...
Authors: Alison K Lee, Christie C Sze, Elaine R Kim and Yuichiro Suzuki
During their evolution towards a complete life cycle on land, stem reptiles developed both an impermeable multi-layered keratinized epidermis and skin appendages (scales) providing mechanical, thermal, and che...
