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Evolution & Development

Takeo Kuriyama, Masami Hasegawa
The combination of body stripes and vivid blue tail color has independently evolved in different lizard families. To understand how and when lizards developed this coloration, we microscopically compared the embryonic development of pigment cells in two island populations of Plestiodon latiscutatus that exhibit either striped and blue tailed or inconspicuously striped and blue tailed juveniles, based on the newly determined 12 normal developmental stages of embryos from shortly after egg laying to just before hatching...
November 23, 2016: Evolution & Development
Shuhei Niitsu, Hirotaka Sugawara, Fumio Hayashi
The evolution of winglessness in insects has been typically interpreted as a consequence of developmental and other adaptations to various environments that are secondarily derived from a winged morph. Several species of bagworm moths (Insecta: Lepidoptera, Psychidae) exhibit a case-dwelling larval life style along with one of the most extreme cases of sexual dimorphism: wingless female adults. While the developmental process that led to these wingless females is well known, the origins and evolutionary transitions are not yet understood...
November 21, 2016: Evolution & Development
Julieta Carril, Claudia P Tambussi
The ossification sequence of Myiopsitta monachus was determined. Myiopsitta has a similar sequence to other altricial birds, with delayed skeletons compared to precocial species. The hindlimbs ossify before the forelimbs, a condition that could be linked to altriciality. To determine the stability of the sequences of ossification across birds, we selected species of different groups of Aves and used event-pairing method and character mapping on a phylogeny. Our results show that the homogeneity in the development of birds was supported by 56...
November 21, 2016: Evolution & Development
Constanze Bickelmann, Wessel van der Vos, Merijn A G de Bakker, Rafael Jiménez, Saskia Maas, Marcelo R Sánchez-Villagra
Fossorial talpid moles use their limbs predominantly for digging, which explains their highly specialized anatomy. The humerus is particularly short and dorsoventrally rotated, with broadened distal and proximal parts where muscles attach and which facilitate powerful abductive movements. The radius and ulna are exceptionally robust and short. The ulna has an expanded olecranon process. The femur is generalized, but the fused tibia-fibula complex is short and robust. To understand the developmental bases of these specializations, we studied expression patterns of four 5' Hox genes in the fossorial Iberian mole (Talpa occidentalis)...
January 2017: Evolution & Development
Muhammad T Raj, Julia C Boughner
Vertebrate jaws and dentitions fit and function together, yet the genetic processes that coordinate cranial and dental morphogenesis and evolution remain poorly understood. Teeth but not jaws fail to form in the edentate p63(-/-) mouse mutant, which we used here to identify genes important to odontogenesis, but not jaw morphogenesis, and that may allow dentitions to change during development and evolution without necessarily affecting the jaw skeleton. With the working hypothesis that tooth and jaw development are autonomously controlled by discreet gene regulatory networks, using gene expression microarray assays validated by quantitative reverse-transcription PCR we contrasted expression in mandibular prominences at embryonic days (E) 10-13 of mice with normal lower jaw development but either normal (p63(+/-) , p63(+/+) ) or arrested (p63(-/-) ) tooth development...
December 2016: Evolution & Development
Marco Romano
No abstract text is available yet for this article.
December 2016: Evolution & Development
Cameron J Weadick, Ralf J Sommer
Patterns of senescence (or aging) can vary among life history traits and between the sexes, providing an opportunity to study variation in the aging process within a single species. We previously found that females of the nematode Pristionchus exspectatus outlive males by a substantial margin under laboratory conditions. Here, we show that sex-specific reproductive senescence unfolds in the opposite direction in this species, resulting in a prolonged period of female-specific post-reproductive survival: females lost the ability to reproduce at approximately 4...
December 2016: Evolution & Development
Eric R Schuppe, Tessa K Solomon-Lane, Devaleena S Pradhan, Kevin Thonkulpitak, Matthew S Grober
Although early exposure to androgens is necessary to permanently organize male phenotype in many vertebrates, animals that exhibit adult sexual plasticity require mechanisms that prevent early fixation of genital morphology and allow for genital morphogenesis during adult transformation. In Lythrypnus dalli, a teleost fish that exhibits bi-directional sex change, adults display dimorphic genitalia morphology despite the absence of sex differences in the potent fish androgen 11-ketotestosterone. Based on conserved patterns of vertebrate development, two steroid-based mechanisms may regulate the early development and adult maintenance of dimorphic genitalia; local androgen receptor (AR) and steroidogenic enzyme expression...
December 2016: Evolution & Development
John A Cunningham, Kelly Vargas, Federica Marone, Stefan Bengtson, Philip C J Donoghue
Three-dimensional analyses of the early Ediacaran microfossils from the Weng'an biota (Doushantuo Formation) have focused predominantly on multicellular forms that have been interpreted as embryos, and yet they have defied phylogenetic interpretation principally because of absence of evidence from other stages in their life cycle. It is therefore unfortunate that the affinities of the various other Doushantuo microfossils have been neglected. A new conical fossil that is preserved at a cellular level is described here...
December 2016: Evolution & Development
Savvas J Constantinou, Ryan M Pace, A J Stangl, Lisa M Nagy, Terri A Williams
Wnt genes are a family of conserved glycoprotein ligands that play a role in a wide variety of cell and developmental processes, from cell proliferation to axis elongation. There are 13 Wnt subfamilies found among metazoans. Eleven of these appear conserved in arthropods with a pattern of loss during evolution of as many as six subfamilies among hexapods. Here we report on Wnt genes in the branchiopod crustacean, Thamnocephalus platyurus, including the first documentation of the expression of the complete Wnt gene family in a crustacean...
December 2016: Evolution & Development
Tara Fresques, Steven Zachary Swartz, Celina Juliano, Yoshiaki Morino, Mani Kikuchi, Koji Akasaka, Hiroshi Wada, Mamiko Yajima, Gary M Wessel
Specification of the germ cell lineage is required for sexual reproduction in all animals. However, the timing and mechanisms of germ cell specification is remarkably diverse in animal development. Echinoderms, such as sea urchins and sea stars, are excellent model systems to study the molecular and cellular mechanisms that contribute to germ cell specification. In several echinoderm embryos tested, the germ cell factor Vasa accumulates broadly during early development and is restricted after gastrulation to cells that contribute to the germ cell lineage...
July 2016: Evolution & Development
Kimberly Suk-Ying Wong, Cesar Arenas-Mena
The expression of transcription factors with endodermal and mesodermal roles in bilaterians is characterized during the development of Hydroides elegans, a serpulid polychaete with planktotrophic trochophore. GATA 4/5/6 is expressed in endodermal and mesodermal precursors during embryogenesis and in the midgut of trochophore larvae. HeGATA1/2/3a is expressed in animal hemisphere blastomeres 1d121 and 1d122, in dorsal ectoderm and in 4d endomesodermal derivatives that maintain their expression in trochophore larvae...
July 2016: Evolution & Development
Tessa K Solomon-Lane, Polina Shvidkaya, Alma Thomas, Megan M Williams, Andrew Rhyne, Lock Rogers, Matthew S Grober
Both individual sex and population sex ratio can affect lifetime reproductive success. As a result, multiple mechanisms have evolved to regulate sexual phenotype, including adult sex change in fishes. While adult sex change is typically socially regulated, few studies focus on the non-chromosomal mechanisms regulating primary sex allocation. We investigated primary sex determination in the bluebanded goby (Lythrypnus dalli), a bidirectionally sex-changing fish. Of the studies investigating primary sex determination in species with adult sex change, this is the first to incorporate the roles of social status and size, key factors for determining adult sex allocation...
July 2016: Evolution & Development
Ingmar Werneburg, Michel Laurin, Daisuke Koyabu, Marcelo R Sánchez-Villagra
Mammals feature not only great phenotypic disparity, but also diverse growth and life history patterns, especially in maturity level at birth, ranging from altriciality to precocity. Gestation length, morphology at birth, and other markers of life history are fundamental to our understanding of mammalian evolution. Based on the first synthesis of embryological data and the study of new ontogenetic series, we reconstructed estimates of the ancestral chronology of organogenesis and life-history modes in placental mammals...
July 2016: Evolution & Development
Nadine Stecher, Annette Stowasser, Aaron Stahl, Elke K Buschbeck
Stemmata, the larval eyes of holometabolous insects are extremely diverse, ranging from full compound eyes, to a few ommatidial units as are typical in compound eyes, to sophisticated and functionally specialized image-forming camera-type eyes. Stemmata evolved from a compound eye ommatidial ancestor, an eye type that is morphologically well conserved in regards to cellular composition, and well studied in regards to development. However, despite this evolutionary origin it remains largely unknown how stemmata develop...
July 2016: Evolution & Development
(no author information available yet)
No abstract text is available yet for this article.
July 2016: Evolution & Development
Sarah A Signor, Michelle N Arbeitman, Sergey V Nuzhdin
Animal development is the product of distinct components and interactions-genes, regulatory networks, and cells-and it exhibits emergent properties that cannot be inferred from the components in isolation. Often the focus is on the genotype-to-phenotype map, overlooking the process of development that turns one into the other. We propose a move toward micro-evolutionary analysis of development, incorporating new tools that enable cell type resolution and single-cell microscopy. Using the sex determination pathway in Drosophila to illustrate potential avenues of research, we highlight some of the questions that these emerging technologies can address...
May 2016: Evolution & Development
P Piras, L Teresi, L Traversetti, V Varano, S Gabriele, T Kotsakis, P Raia, P E Puddu, M Scalici
Ontogeny is usually studied by analyzing a deformation series spanning over juvenile to adult shapes. In geometric morphometrics, this approach implies applying generalized Procrustes analysis coupled with principal component analysis on multiple individuals or multiple species datasets. The trouble with such a procedure is that it mixes intra- and inter-group variation. While MANCOVA models are relevant statistical/mathematical tools to draw inferences about the similarities of trajectories, if one wants to observe and interpret the morphological deformation alone by filtering inter-group variability, a particular tool, namely parallel transport, is necessary...
May 2016: Evolution & Development
Philip S L Anderson, Danielle C Smith, S N Patek
Related species that share similar biomechanical systems and segmentation patterns may exhibit different patterns of morphological covariation. We examined morphological covariation of the potent prey capture appendage of two mantis shrimp (Stomatopoda) species-a spearer (Squilla empusa) and smasher (Gonodactylaceus falcatus). We assessed three frameworks for modularity, two based on the biomechanics of the appendage and one based on its segmentation as a proxy for shared developmental pathways. We collected morphometric data from S...
May 2016: Evolution & Development
Caleb Jones, Theodore Stankowich, Bruno Pernet
Evolutionary transitions between feeding and nonfeeding larval development have occurred many times in marine invertebrates, but the developmental changes underlying these frequent and ecologically important transitions are poorly known, especially in spiralians. We use phylogenetic comparative methods to test the hypothesis that evolutionary changes in egg size and larval nutritional mode are associated with parallel changes in allocation of cytoplasm to macromere cell lineages in diverse annelids and molluscs...
May 2016: Evolution & Development
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