4,081 research outputs found

    Thinking Adaptive: Towards a Behaviours Virtual

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    In this paper we name some of the advantages of virtual laboratories; and propose that a Behaviours Virtual Laboratory should be useful for both biologists and AI researchers, offering a new perspective for understanding adaptive behaviour. We present our development of a Behaviours Virtual Laboratory, which at this stage is focused in action selection, and show some experiments to illustrate the properties of our proposal, which can be accessed via Internet

    The Central role of KNG1 gene as a genetic determinant of coagulation pathway-related traits: Exploring metaphenotypes

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    Traditional genetic studies of single traits may be unable to detect the pleiotropic effects involved in complex diseases. To detect the correlation that exists between several phenotypes involved in the same biological process, we introduce an original methodology to analyze sets of correlated phenotypes involved in the coagulation cascade in genome-wide association studies. The methodology consists of a two-stage process. First, we define new phenotypic meta-variables (linear combinations of the original phenotypes), named metaphenotypes, by applying Independent Component Analysis for the multivariate analysis of correlated phenotypes (i.e. the levels of coagulation pathway–related proteins). The resulting metaphenotypes integrate the information regarding the underlying biological process (i.e. thrombus/clot formation). Secondly, we take advantage of a family based Genome Wide Association Study to identify genetic elements influencing these metaphenotypes and consequently thrombosis risk. Our study utilized data from the GAIT Project (Genetic Analysis of Idiopathic Thrombophilia). We obtained 15 metaphenotypes, which showed significant heritabilities, ranging from 0.2 to 0.7. These results indicate the importance of genetic factors in the variability of these traits. We found 4 metaphenotypes that showed significant associations with SNPs. The most relevant were those mapped in a region near the HRG, FETUB and KNG1 genes. Our results are provocative since they show that the KNG1 locus plays a central role as a genetic determinant of the entire coagulation pathway and thrombus/clot formation. Integrating data from multiple correlated measurements through metaphenotypes is a promising approach to elucidate the hidden genetic mechanisms underlying complex diseases.Postprint (published version

    Biomechanics of <i>Machaeracanthus</i> pectoral fin spines provide evidence for distinctive spine function and lifestyle among early chondrichthyans

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    Acanthodians are a major group of Paleaozoic jawed vertebrates that constitute a paraphyletic assemblage of stem-chondrichthyans (Brazeau and Friedman, 2015). Representatives of this group are characterized, among other traits, by the presence of bony spines in front of all paired and median fins except the caudal (Denison, 1979), which has given rise to their colloquial name of 'spiny sharks'. The occurrence of pectoral fin spines is recognized as a potential gnathostome synapomorphy (Miller et al., 2003) or symplesiomorphy (Coates, 2003), being also present in other major groups of Paleaozoic jawed vertebrates, including placoderms (Young, 2010), 'non-acanthodian' chondrichthyans (Miller et al., 2003), and osteichthyans (Zhu et al., 1999). However, this trait was independently lost in the later evolutionary history of these lineages and is absent in most living representatives (Coates, 2003; Miller et al., 2003), with the exception of catfishes (Siluriformes), that acquired pectoral fin spines as an evolutionary reversion (Price et al., 2015). As a consequence, the paucity of living analogsue precludes deriving functional interpretations of those structures and the role that they fulfilled in life remains unclear, despite this having the potential to enrich our understanding on the ecologies and lifestyles of groups of early jawed vertebrates. Machaeracanthus constitutes a genus of acanthodians that ranged from the Late Silurian to the Middle Devonian, which is known from fin spines, scales, and a few endoskeletal remains (Burrow et al., 2010; Botella et al., 2012). The spines of this genus differ from the fin spines of all other acanthodians and sharks in presenting a marked cross-sectional asymmetry and a totally enclosed central canal, which is usually open along the proximal end of the trailing edge in other taxa (Burrow et al., 2010). The description of wear patterns at the tips of pectoral fin spines of Machaeracanthus and their peculiar arrangement in pairs has led some authors to propose that these elements could have been used as 'snow-shoes' to lay on and prevent sinking into the substrate below or even to propel itself along the bottom (Südkamp and Burrow, 2007). Here, we test this hypothesis through beam theory analyses and provide evidence that the biomechanical properties of Machaeracanthus pectoral fin spines are compatible with this interpretation, thus shedding light on the diversity of the functions of these intriguing anatomical structures and the lifestyles of some of the earliest jawed vertebrates
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