Project description:Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Palaeo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Palaeo-Inuit dogs, and probably aided the Inuit expansion across the North American Arctic beginning around 1000 BP.
Project description:Transcriptional profiling of dog muscle tissue comparing control dogs. tested, genomewide, for genes differentially expressed in muscle between the escapers and the affected dogs. Using Agilent mRNA SurePrint Canine arrays, we compared muscle gene expression of the two escapers, four affected, and four normal dogs at age 2 years.
Project description:The objective of this study was to identify the different functional genes involved in key biogeochemical cycles in the low Arctic regions. Understanding the microbial diversity in the Arctic region is an important step to determine the effects of climate change on these areas.
Project description:C5aR1, a receptor for the complement activation proinflammatory fragment, C5a, is primarily expressed on cells of the myeloid lineage, and to a lesser extent on endothelial cells and neurons in brain. Previous work demonstrated C5aR1 antagonist, PMX205, decreased amyloid pathology and suppressed cognitive deficits in Alzheimer Disease (AD) mouse models. In the Arctic AD mouse model, genetic deletion of C5aR1 prevented behavior deficits at 10 months. However, the molecular mechanisms of this protection has not been definitively demonstrated. To understand the role of microglial C5aR1 in the Arctic AD mouse model, we have taken advantage of the CX3CR1GFP and CCR2RFP reporter mice to distinguish microglia as GFP-positive and infiltrating monocytes as GFP and RFP positive, for subsequent transcriptome analysis on specifically sorted myeloid populations from wild type and AD mouse models. Immunohistochemical analysis of mice aged to 2, 5, 7 and 10 months showed no change in amyloid beta (Ab) deposition in the Arctic C5aR1 knockout (KO) mice relative to that seen in the Arctic mice. Of importance, no CCR2+ monocytes/macrophages were found near the plaques in the Arctic brain with or without C5aR1. RNA-seq analysis on microglia from these mice identified inflammation related genes as differentially expressed, with increased expression in the Arctic mice relative to wildtype and decreased expression in the Arctic/C5aR1KO relative to Arctic. In addition, phagosomal-lysosomal proteins and protein degradation pathways that were increased in the Arctic mice were further increased in the Arctic/C5aR1KO mice. These data are consistent with a microglial polarization state with restricted induction of inflammatory genes and enhancement of clearance pathways.
Project description:Development and progression of myxomatous mitral valve disease (MMVD) in domestic dogs is unpredictable and pathobiology still unclear. The American College of Veterinary Internal Medicine (ACVIM) perceived that mayor improvement in management of diseased dogs would be timely diagnosis, especially detection of transition from MMVD stage B1 into B2. Thus, in this study we compared by tandem mass tag (TMT) protocol and mass spectrometry (MS) acquired quantitative proteome profiles of serum collected from healthy (control) (N=12) and dogs diagnosed with different stages of naturally occurring MMVD: B1 (N=13), B2 (N=12) and C (N=13). Prior to proteomic analysis dogs were distinguished into experimental categories based on echocardiography results. Serum biochemistry and concentrations of three cardiac biomarkers (galectin-3, suppression of tumorigenicity 2 and asymmetric dimethylarginine) were performed to obtain better characterization of healthy/control group and MMVD cases.
Project description:Analysis of microbial community composition in arctic tundra and boreal forest soils using serial analysis of ribosomal sequence tags (SARST). Keywords: other