Biology subjects

Savage, J.

Publications and source records attributed to Savage, J..

5 recordsLinked to original sources

bioRxiv2018

The role of tactile interactions in flight responses in the Bronze Cory catfish (Corydoras aeneus)

One of the primary functions of animal aggregations is defense against predators. Many social animals enjoy reduced predation risk as a result of grouping, and individuals within groups can benefit from information transferred by their group-mates about a potential predator. We present evidence that a tactile interaction behavior we term nudging substantially modified group responses to a potential threat in a highly social catfish species, Corydoras aeneus. These catfish deployed nudges during flight responses, and these nudges were associated with a greater likelihood of group cohesion following a threat event. Increased nudging behavior resulted in longer flight responses. In addition, individuals that perceived the threat first were more likely to initiate nudges, implying that nudges could be used to alert group-mates to the presence of a threat. Taken together, our results suggest that tactile communication plays an important role in gaining anti-predator benefits from sociality in these fish.

animal behavior and cognition↗

bioRxiv2018

Genetic meta-analysis identifies 10 novel loci and functional pathways for Alzheimer’s disease risk

Late onset Alzheimers disease (AD) is the most common form of dementia with more than 35 million people affected worldwide, and no curative treatment available. AD is highly heritable and recent genome-wide meta-analyses have identified over 20 genomic loci associated with AD, yet only explaining a small proportion of the genetic variance indicating that undiscovered loci exist. Here, we performed the largest genome-wide association study of clinically diagnosed AD and AD-by-proxy (71,880 AD cases, 383,378 controls). AD-by-proxy status is based on parental AD diagnosis, and showed strong genetic correlation with AD (rg=0.81). Genetic meta analysis identified 29 risk loci, of which 9 are novel, and implicating 215 potential causative genes. Independent replication further supports these novel loci in AD. Associated genes are strongly expressed in immune-related tissues and cell types (spleen, liver and microglia). Furthermore, gene-set analyses indicate the genetic contribution of biological mechanisms involved in lipid-related processes and degradation of amyloid precursor proteins. We show strong genetic correlations with multiple health-related outcomes, and Mendelian randomisation results suggest a protective effect of cognitive ability on AD risk. These results are a step forward in identifying more of the genetic factors that contribute to AD risk and add novel insights into the neurobiology of AD to guide new drug development.

genetics↗

bioRxiv2017

Infant Weight Gain Trajectories Linked To Oral Microbiome Composition

Gut and oral microbiome perturbations have been observed in obese adults and adolescents. Less is known about how weight gain in early childhood is influenced by gut, and particularly oral, microbiomes. Here we analyze the relationships among weight gain and gut and oral microbiomes in 226 two-year-olds who were followed during the first two years of life, as part of a larger study, with weight and length measured at seven time points. We used these data to identify children with rapid weight gain (a strong risk factor for childhood obesity), and to derive growth curves with novel Functional Data Analysis (FDA) techniques. The childrens oral and gut microbiomes were sampled at the end of the two-year period, and surveyed with 16S sequencing. First, we show that growth curves are associated negatively with diversity and positively with Firmicutes-to-Bacteroidetes ratio of the oral microbiome - a relationship that is also observed in children with rapid (vs. non-rapid) weight gain. We also demonstrate an association between the gut microbiome and child growth, but only when considering the effect of diet on the microbiome. Lastly, we identify several bacterial genera that are associated with child growth patterns. These results suggest that by the age of two, the oral microbiome may have already begun to establish patterns often seen in older obese individuals. They also suggest that the gut microbiome, while strongly influenced by diet, at age two does not harbor obesity signatures many researchers identified in later life stages.

genomics↗

bioRxiv2017

Mid-Infrared Spectroscopy Study of Effects of Neonicotinoids on Forager Honey Bee (Apis mellifera) Fat Bodies and Their Connection to Colony Collapse Disorder

This study investigated the negative effects of neonicotinoid pesticides on honey bees in environment surrounding areas of pesticide use. The aim of the experiment is to identify possible contributors to the sudden decrease in honey bee population over the past 60 years, a phenomenon known as Colony Collapse Disorder. Analysis was performed on three sets of bees: the control group which was not in contact with pesticides, the infected dead group which was a set of bees suspected to have died due to neonicotinoids, and the infected alive group which was suspected to be under the influence of neonicotinoids. After dissecting the bee samples and extracting their fat bodies, the chemical composition and protein structures of the samples were analyzed using Mid-Infrared Beamline at the Canadian Light Source. Results from the spectra of bee samples exposed to neonicotinoids demonstrated possible residual pesticide chemicals within fat bodies. Several spectral peaks were also correlated with a possible change in protein secondary structures from primarily {beta}-sheet to -helix within fat bodies of neonicotinoid-affected bees. It is likely that the pesticides caused the growth of additional -helical structures, which is consistent with consequences of the inhibition of nicotinic acetylcholine receptors (nAChRs) a current pathway of harm of Colony Collapse Disorder as identified in past literature.

pharmacology and toxicology↗

bioRxiv2017

Functional consequences of genetic loci associated with intelligence in a meta-analysis of 87,740 individuals

Variance in IQ is associated with a wide range of health outcomes, and 1% of the population are affected by intellectual disability. Despite a century of research, the fundamental neural underpinnings of intelligence remain unclear. We integrate results from genome-wide association studies (GWAS) of intelligence with brain tissue and single cell gene expression data to identify tissues and cell types associated with intelligence. GWAS data for IQ (N = 78,308) were meta-analyzed with an extreme-trait cohort of 1,247 individuals with mean IQ [~]170 and 8,185 controls. Genes associated with intelligence implicate pyramidal neurons of the somatosensory cortex and CA1 region of the hippocampus, and midbrain embryonic GABAergic neurons. Tissue-specific analyses find the most significant enrichment for frontal cortex brain expressed genes. These results suggest specific neuronal cell types and genes may be involved in intelligence and provide new hypotheses for neuroscience experiments using model systems.

genomics↗