Feeding habits of extant and fossil canids as determined by their skull geometry

The canids belong to one of the most prominent families of mammalian carnivores. Feeding adaptations of extant species is well documented by field observations; however, we are still missing palaeoecological insights for many enigmatic fossil specimens. We employ geometric morphometrics to quantify skull size and shape in extant and fossil members of the Canini tribe, inclusive of jackals and wolf-like taxa. Skull data are tested to identify correlates of dietary adaptations in extant species for predicting adaptations in fossils. Main vectors of shape variation correlate with the relative skull-palatal length, the position of the upper carnassial tooth and the anterior tip of the secondary palate. Allometry occurs in the palatal shape but size explains only a small fraction (about 4%) of shape variance. Although we quantified only palatal and tooth shape for the inclusion of fragmentary fossils, discriminant function analysis successfully classify extant Canini in dietary groups (small, medium and large prey specialist) with 89% of accuracy. The discriminant functions provide insights into many enigmatic specimens such as Eucyon adoxus (=small prey), fossil jackal-like from Koobi Fora formation (=small prey) and the Plio-Pleistocene Old World canid guild (Canis etruscus, C. arnensis and Lycaon falconeri). Clearly, both skull size and shape are excellent predictors of feeding habits in Canini thus also provide information about fossil taxonomic affinities

Genome of the marsupial Monodelphis domestica reveals innovation in non-coding sequences

We report a high-quality draft of the genome sequence of the grey, short-tailed opossum (Monodelphis domestica). As the first metatherian (‘marsupial’) species to be sequenced, the opossum provides a unique perspective on the organization and evolution of mammalian genomes. Distinctive features of the opossum chromosomes provide support for recent theories about genome evolution and function, including a strong influence of biased gene conversion on nucleotide sequence composition, and a relationship between chromosomal characteristics and X chromosome inactivation. Comparison of opossum and eutherian genomes also reveals a sharp difference in evolutionary innovation between protein-coding and non-coding functional elements. True innovation in protein-coding genes seems to be relatively rare, with lineage-specific differences being largely due to diversification and rapid turnover in gene families involved in environmental interactions. In contrast, about 20% of eutherian conserved non-coding elements (CNEs) are recent inventions that postdate the divergence of Eutheria and Metatheria. A substantial proportion of these eutherian-specific CNEs arose from sequence inserted by transposable elements, pointing to transposons as a major creative force in the evolution of mammalian gene regulation

Polygenic risk score-based phenome-wide association study identifies novel associations for Tourette syndrome

AbstractTourette Syndrome (TS) is a complex neurodevelopmental disorder characterized by vocal and motor tics lasting more than a year. It is highly polygenic in nature with both rare and common previously associated variants. Epidemiological studies have shown TS to be correlated with other phenotypes, but large-scale phenome wide analyses in biobank level data have not been performed to date. In this study, we used the summary statistics from the latest meta-analysis of TS to calculate the polygenic risk score (PRS) of individuals in the UK Biobank data and applied a Phenome Wide Association Study (PheWAS) approach to determine the association of disease risk with a wide range of phenotypes. A total of 57 traits were found to be significantly associated with TS polygenic risk, including multiple psychosocial factors and mental health conditions such as anxiety disorder and depression. Additional associations were observed with complex non-psychiatric disorders such as Type 2 diabetes, heart palpitations, and respiratory conditions. Cross-disorder comparisons of phenotypic associations with genetic risk for other childhood-onset disorders (e.g.: attention deficit hyperactivity disorder [ADHD], autism spectrum disorder [ASD], and obsessive-compulsive disorder [OCD]) indicated an overlap in associations between TS and these disorders. ADHD and ASD had a similar direction of effect with TS while OCD had an opposite direction of effect for all traits except mental health factors. Sex-specific PheWAS analysis identified differences in the associations with TS genetic risk between males and females. Type 2 diabetes and heart palpitations were significantly associated with TS risk in males but not in females, whereas diseases of the respiratory system were associated with TS risk in females but not in males. This analysis provides further evidence of shared genetic and phenotypic architecture of different complex disorders.</jats:p