Some recent non-dino papers:
Neil Gemmell, Kim Rutherford, Stefan Prost, Marc Tollis, David J Winter, J. Robert Macey, David L Adelson, Alexander Suh, Terry Bertozzi, Josà Grau, Chris Organ, Paul Gardner, Matthieu Muffato, Mateus Patricio, Konstantinos Billis, Fergal J Martin, Paul Flicek, Bent Petersen, Lin Kang, Pawel Michalak, Thomas Buckley, Melissa A Wilson, Yuanyuan Cheng, Hilary Miller, Ryan K Schott, Melissa Jordan, Richard Newcomb, Josà Ignacio Arroyo, Nicole Valenzuela, Timothy A. Hore, Jaime Renart, Valentina Peona, Claire Peart, Vera Warmuth, LU ZENG, Daniel Kortschak, Joy M. Raison, Valeria VelÃsquez Zapata, Zhiqiang Wu, Didac Santesmasses, Marco Mariotti, Roderic Guigo, Shawn Rupp, Victoria Twort, Nicolas Dussex, Helen R. Taylor, Hideaki Abe, James Paterson, Daniel G. Mulcahy, Vanessa Gonzalez, Charles G. Barbieri, Dustin P. DeMeo, Stephan Pabinger, Oliver A. Ryder, Scott V. Edwards, Steven Salzberg, Lindsay Mickelson, Nicola Nelson, Clive Stone & Ngatiwai Trust Board (2019)
The tuatara genome: insights into vertebrate evolution from the sole survivor of an ancient reptilian order.
bioRxiv (preprint)
doi:
https://doi.org/10.1101/867069https://www.biorxiv.org/content/10.1101/867069v1Free pdf:
https://www.biorxiv.org/content/biorxiv/early/2019/12/08/867069.full.pdf
The tuatara (Sphenodon punctatus), the only living member of the archaic reptilian order Rhynchocephalia (Sphenodontia) once widespread across Gondwana, is an iconic and enigmatic terrestrial vertebrate endemic to New Zealand. A key link to the now extinct stem reptiles from which dinosaurs, modern reptiles, birds and mammals evolved, the tuatara provides exclusive insights into the ancestral amniotes. The tuatara genome, at ~5 Gbp, is among the largest vertebrate genomes assembled. Analysis of this genome and comparisons to other vertebrates reinforces the uniqueness of the tuatara. Phylogenetic analyses indicate tuatara diverged from the snakes and lizards ~250 MYA. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Genome sequence analysis identifies expansions of protein, non-protein-coding RNA families, and repeat elements, the latter of which show an extraordinary amalgam of reptilian and mammalian features. Sequencing of this genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. It also provides important insights into both the technical challenges and the cultural obligations associated with genome sequencing.
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Free pdf:
Genome size has long been hypothesized to affect metabolic rate in various groups of animals. The mechanism behind this proposed association is the nucleotypic effect, in which large nucleus and cell sizes influence cellular metabolism through surface area-to-volume ratios. Here, we provide a review of the recent literature on the relationship between genome size and metabolic rate. We also conduct an analysis using phylogenetic comparative methods and a large sample of extant vertebrates. We find no evidence that the effect of genome size improves upon models in explaining metabolic rate variation. Not surprisingly, our results show a strong positive relationship between metabolic rate and body mass, as well as a substantial difference in metabolic rate between endothermic and ectothermic vertebrates, controlling for body mass. The presence of endothermy can also explain elevated rate shifts in metabolic rate whereas genome size cannot. We further find no evidence for a punctuated model of evolution for metabolic rate. Our results do not rule out the possibility that genome size affects cellular physiology in some tissues, but they are consistent with previous research suggesting little support for a direct functional connection between genome size and basal metabolic rate in extant vertebrates.
Marie Landova Sulcova, Oldrich Zahradnicek, Jana Dumkova, Hana Dosedelova, Jan Krivanek, Marek Hampl, Michaela Kavkova, Tomas Zikmund, Martina Gregorovicova, David Sedmera, Jozef Kaiser, Abigail S. Tucker & Marcela Buchtova (2019)
Developmental mechanisms driving complex tooth shape in reptiles.
Developmental Dynamics (advance online publication)
doi:
https://doi.org/10.1002/dvdy.138https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/dvdy.138Background
In mammals, odontogenesis is regulated by transient signaling centers known as enamel knots (EKs), which drive the dental epithelium shaping. However, the developmental mechanisms contributing to formation of complex tooth shape in reptiles are not fully understood. Here, we aim to elucidate whether signaling organizers similar to EKs appear during reptilian odontogenesis and how enamel ridges are formed.
Results
Morphological structures resembling the mammalian EK were found during reptile odontogenesis. Similar to mammalian primary EKs, they exhibit the presence of apoptotic cells and no proliferating cells. Moreover, _expression_ of mammalian EKâspecific molecules (SHH, FGF4 and ST14) and GLI2ânegative cells were found in reptilian EKâlike areas. 3D analysis of the nucleus shape revealed distinct rearrangement of the cells associated with enamel groove formation. This process was associated with ultrastructural changes and lipid droplet accumulation in the cells directly above the forming ridge, accompanied by alteration of membranous molecule _expression_ (Na/KâATPase) and cytoskeletal rearrangement (Fâactin).
Conclusions
The final complex shape of reptilian teeth is orchestrated by a combination of changes in cell signaling, cell shape and cell rearrangement. All these factors contribute to asymmetry in the inner enamel epithelium development, enamel deposition, ultimately leading to the formation of characteristic enamel ridges.