The developmental stages of feathers are of major importance in the evolution of body covering and the origin of avian flight. Until now, there were significant gaps in knowledge of early morphologies in theoretical stages of feathers as well as in palaeontological material. Here we report fossil evidence of an intermediate and critical stage in the incremental evolution of feathers which has been predicted by developmental theories but hitherto undocumented by evidence from both the recent and the fossil records. Seven feathers have been found in an Early Cretaceous (Late Albian, ca 100 Myr) amber of western France, which display a flattened shaft composed by the still distinct and incompletely fused bases of the barbs forming two irregular vanes. Considering their remarkably primitive features, and since recent discoveries have yielded feathers of modern type in some derived theropod dinosaurs, the Albian feathers from France might have been derived either from an early bird or from a non-avian dinosaur.
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http://dx.doi.org/10.1098/rspb.2008.0003 | DOI Listing |
BMC Genomics
December 2024
Department of Biological Sciences, University of Bergen, Bergen, N-5020, Norway.
Background: Fervidobacterium is a genus of thermophilic anaerobic Gram-negative rod-shaped bacteria belonging to the phylum Thermotogota. They can grow through fermentation on a wide range of sugars and protein-rich substrates. Some can also break down feather keratin, which has significant biotechnological potential.
View Article and Find Full Text PDFGenome Biol Evol
December 2024
Department of Dermatology, Medical University of Vienna, Vienna, Austria.
The evolution of cornified skin appendages, such as hair, feathers and claws, is closely linked to the evolution of proteins that establish the unique mechanical stability of these epithelial structures. We hypothesized that the evolution of the limbless body anatomy of the Florida worm lizard (Rhineura floridana) and the concomitant loss of claws had led to the degeneration of genes with claw-associated functions. To test this hypothesis, we investigated the evolution of three gene families implicated in epithelial cell architecture, namely type I keratins, type II keratins and genes of the epidermal differentiation complex (EDC) in R.
View Article and Find Full Text PDFAnimals (Basel)
November 2024
Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås, Norway.
The hypothalamic-pituitary-adrenal (HPA) axis responsivity is influenced by early life experience and also modified by the environment an individual experiences as an adult. Because laying hens are transferred from rearing to laying farms at 16-18 weeks of age, they are well suited to study the interaction effect between early (rearing) and adult (laying) environments on physiology and behaviour. In the European Union, there is a move towards cage-free systems for laying hens, but globally, the majority of layers are kept in conventional or furnished cages.
View Article and Find Full Text PDFJ Exp Biol
December 2024
Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA.
Science
December 2024
Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.
Despite the well-known effects of sexual selection on phenotypes, links between this evolutionary process and reproductive isolation, genomic divergence, and speciation have been difficult to establish. We unravel the genetic basis of sexually selected plumage traits to investigate their effects on reproductive isolation in barn swallows. The genetic architecture of sexual traits is characterized by 12 loci on two autosomes and the Z chromosome.
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