Project description:Birds and other reptiles possess a diversity of feather and scale-like skin appendages. Feathers are commonly assumed to have originated from ancestral scales in theropod dinosaurs. However, most birds also have scaled feet, indicating birds evolved the capacity to grow both ancestral and derived morphologies. This suggests a more complex evolutionary history than a simple linear transition between feathers and scales. We set out to investigate the evolution of feathers via the comparison of transcriptomes assembled from diverse skin appendages in chicken, emu, and alligator. Our data reveal that feathers and the overlapping ‘scutate’ scales of birds share more similar gene expression to each other, and to two types of alligator scales, than they do to the tuberculate ‘reticulate’ scales on bird footpads. Accordingly, we propose a history of skin appendage diversification, in which feathers and bird scutate scales arose from ancestral archosaur body scales, whereas reticulate scales arose earlier in tetrapod evolution. We also show that many “feather-specific genes” are also expressed in alligator scales. In-situ hybridization results in feather buds suggest that these genes represent ancestral scale genes that acquired novel roles in feather morphogenesis and were repressed in bird scales. Our findings suggest that the differential reuse, in feathers, and suppression, in bird scales, of genes ancestrally expressed in archosaur scales has been a key factor in the origin of feathers – and may represent an important mechanism for the origin of evolutionary novelties.
Project description:Comparative genomic hybridisation of genomic DNA from avian species to the Roche NimbleGen chicken whole genome oligonucleotide array. The purpose was to identify copy number variants between the given species and chicken. The starting material was blood or feather pulp from a variety of bird species, from which we performed DNA extractions.
Project description:For a long time, Neanderthals were considered hunters of large mammals, whereas the diversification of the exploited faunal spectrum to include smaller taxa, including birds, was assumed to be specific to anatomically modern humans. In recent decades, archaeozoological analyses of faunal remains from layers associated with Middle Palaeolithic lithic industries have revealed traces of human manipulation of small taxa, indicating the exploitation of a wider range of animals than previously thought, including small or fast-moving animals such as molluscs, leporids and birds. These new data have challenged the view that Neanderthals did not exploit small animals, thereby narrowing the behavioral gap with anatomically modern humans. Nevertheless, the information currently available comes almost exclusively from southern Europe and the nature of Neanderthal small fauna exploitation in northern Europe remains largely unknown. The present study aims to fill this gap by applying archaeozoological methods, including detailed taphonomic and traceological analyses, to 118 bird remains recovered from levels containing Middle Palaeolithic industries at Scladina cave, southern Belgium. Analyses of proteomics were applied to clarify the taxonomic identity of two morphologically non-diagnostic elements. Compared to mammal remains, bird bones, most of which belong to the order Galliformes, are scarce at Scladina Cave. This is likely due to conservation bias. Traces of non-human predators or scavengers, suggest that mammalian carnivores are responsible for accumulating a considerable portion of the avian assemblage. In total, seven bird bones exhibit anthropogenic traces, and one element presents questionable traces. Various Galliformes and a cormorant were exploited likely for their meat, during MIS 5 and/or 6 and MIS 6. The terminal posterior phalanx (talon) of a raptor of the size of a pomarine eagle displays intense polishing that could be linked to human manipulation of this element (MIS 5 and/or 6), although in the absence of tool marks this remains hypothetical at this stage. On the radius of a Western capercaillie, two deep incisions may indicate bone working, and intense use-wear on one of the fractured ends indicates that the bone has been utilized, potentially on soft organic material (MIS 6). This study provides the first evidence of the exploitation of birds during the Middle Palaeolithic in Belgium and constitutes the only detailed archaeozoological analysis of bird material in northwestern Europe. The likely transformation and use of a bird bone is only the second example recovered from Neanderthal occupations. The novel taxa identified as Neanderthal prey highlight the plasticity of Neanderthal ecological behavior, adapting to different landscapes and climates and exploiting the full spectrum of locally available prey.
Project description:Even though feather pecking (FP) in laying hens has been extensively studied, a good solution to prevent chickens from this behavior under commercial circumstances has not been found. Selection against FP behavior is possible, but for a more effective selection across different populations, it is necessary to characterize the genetic mechanism associated with this behavior. In this study, we use a high FP selection line, which has been selected for 8 generations. We present evidence of the presence of a major dominant allele affecting the FP behavior by using an argument based on the presence of mixture in the distribution of the observed FP and by studying the evolution of the proportion of very high FP along the sequence of 8 generations. This hypothesis is further supported by the fact that the gene transcription profile of the birds performing high FP differs from the profile of the other birds performing FP (456 genes differentially expressed from a total of 14,077 investigated genes). Keywords: severe feather pecking , selection , modeling , inheritance pattern From each selection line (high feather pecking line, low feather pecking line and control line) 60 animals were randomly selected. Within each line the birds were randomly assigned to a cage of 20. The cages were kept in a randomized block design. Number of samples analyzed in total: 179 (60 high feather pecking line, 60 low feather pecking line, 59 control line samples. Common reference design using total-RNA purified from brain from a single F1 cross between the high and low feather pecking line as reference.
Project description:Flatfish have evolved their visual system to meet the demands of their environment through a fascinating process of metamorphosis. This morphological transformation involves a significant change in lifestyle from pelagic to benthic, accompanied by changes in body structure to achieve an asymmetrical flat shape. However, the fundamental change lies in the migration of one eye from its original position to the opposite location on the body. Although the role of thyroid hormone in triggering flatfish metamorphosis is well established, the specific gene regulatory network responsible for this extraordinary eye migration is still unknown. Here we show a global view through the creation of a general map of gene expression during the metamorphic process, encompassing both migrant and non-migrant eyes. Our research uncovers significant differences between migrant and non-migrant eyes of turbot in the pre-metamorphic and climax phases, emphasizing genetic disparities crucial for benthic adaptation.