An Inversion Disrupting FAM134B Is Associated with Sensory Neuropathy in the Border Collie Dog Breed

Sensory neuropathy in the Border Collie is a severe neurological disorder caused by the degeneration of sensory and, to a lesser extent, motor nerve cells with clinical signs starting between 2 and 7 months of age. Using a genome-wide association study approach with three cases and 170 breed matched controls, a suggestive locus for sensory neuropathy was identified that was followed up using a genome sequencing approach. An inversion disrupting the candidate gene FAM134B was identified. Genotyping of additional cases and controls and RNAseq analysis provided strong evidence that the inversion is causal. Evidence of cryptic splicing resulting in novel exon transcription for FAM134B was identified by RNAseq experiments. This investigation demonstrates the identification of a novel sensory neuropathy associated mutation, by mapping using a minimal set of cases and subsequent genome sequencing. Through mutation screening, it should be possible to reduce the frequency of or completely eliminate this debilitating condition from the Border Collie breed population

Molecular footprints of the Holocene retreat of dwarf birch in Britain

© 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

DNA testing and domestic dogs

There are currently about 80 different DNA tests available for mutations that are associated with inherited disease in the domestic dog, and as the tools available with which to dissect the canine genome become increasingly sophisticated, this number can be expected to rise dramatically over the next few years. With unrelenting media pressure focused firmly on the health of the purebred domestic dog, veterinarians and dog breeders are turning increasingly to DNA tests to ensure the health of their dogs. It is ultimately the responsibility of the scientists who identify disease-associated genetic variants to make sensible choices about which discoveries are appropriate to develop into commercially available DNA tests for the lay dog breeder, who needs to balance the need to improve the genetic health of their breed with the need to maintain genetic diversity. This review discusses some of the factors that should be considered along the route from mutation discovery to DNA test and some representative examples of DNA tests currently available

Modification of cell wall properties in lettuce improves shelf life

It is proposed that post-harvest longevity and appearance of salad crops is closely linked to pre-harvest leaf morphology (cell and leaf size) and biophysical structure (leaf strength). Transgenic lettuce plants (Lactuca sativa cv. Valeria) were produced in which the production of the cell wall-modifying enzyme xyloglucan endotransglucosylase/hydrolase (XTH) was down-regulated by antisense inhibition. Independently transformed lines were shown to have multiple members of the LsXTH gene family down-regulated in mature leaves of 6-week-old plants and during the course of shelf life. Consequently, xyloglucan endotransglucosylase (XET) enzyme activity and action were down-regulated in the cell walls of these leaves and it was established that leaf area and fresh weight were decreased while leaf strength was increased in the transgenic lines. Membrane permeability was reduced towards the end of shelf life in the transgenic lines relative to the controls and bacteria were evident inside the leaves of control plants only. Most importantly, an extended shelf-life of transgenic lines was observed relative to the non-transgenic control plants. These data illustrate the potential for engineering cell wall traits for improving quality and longevity of salad crops using either genetic modification directly, or by using markers associated with XTH genes to inform a commercial breeding programme

Survey sequencing and radiation hybrid mapping to construct comparative maps.

In MURPHY WJ (ed.) Phylogenomics, Humana Press. (Methods in Molecular Biology, 422)International audienceRadiation hybrid (RH) mapping has become one of the most well-established techniques for economically and efficiently navigating genomes of interest. The success of the technique relies on random chromosome breakage of a target genome, which is then captured by recipient cells missing a preselected marker. Selection for hybrid cells that have DNA fragments bearing the marker of choice, plus a random set of DNA fragments from the initial irradiation, generates a set of cell lines that recapitulates the genome of the target organism several-fold. Markers or genes of interest are analyzed by PCR using DNA isolated from each cell line. Statistical tools are applied to determine both the linear order of markers on each chromosome, and the confidence of each placement. The resolution of the resulting map relies on many factors, most notably the degree of breakage from the initial radiation as well as the number of hybrid clones and mean retention value.A high-resolution RH map of a genome derived from low pass or survey sequencing (coverage from 1 to 2 times) can provide essentially the same comparative data on gene order that is derived from high-coverage (greater than x7) genome sequencing. When combined with fluorescence in situ hybridization, RH maps are complete and ordered blueprints for each chromosome. They give information about the relative order and spacing of genes and markers, and allow investigators to move between target and reference genomes, such as those of mouse or human, with ease although the approach is not limited to mammal genomes

Whole Genome Sequencing of Giant Schnauzer Dogs with Progressive Retinal Atrophy Establishes NECAP1 as a Novel Candidate Gene for Retinal Degeneration

Canine progressive retinal atrophies (PRA) are genetically heterogeneous diseases characterized by retinal degeneration and subsequent blindness. PRAs are untreatable and affect multiple dog breeds, significantly impacting welfare. Three out of seven Giant Schnauzer (GS) littermates presented with PRA around four years of age. We sought to identify the causal variant to improve our understanding of the aetiology of this form of PRA and to enable development of a DNA test. Whole genome sequencing of two PRA-affected full-siblings and both unaffected parents was performed. Variants were filtered based on those segregating appropriately for an autosomal recessive disorder and predicted to be deleterious. Successive filtering against 568 canine genomes identified a single nucleotide variant in the gene encoding NECAP endocytosis associated 1 (NECAP1): c.544G>A (p.Gly182Arg). Five thousand one hundred and thirty canids of 175 breeds, 10 cross-breeds and 3 wolves were genotyped for c.544G>A. Only the three PRA-affected GS were homozygous (allele frequency in GS, excluding proband family = 0.015). In addition, we identified heterozygotes belonging to Spitz and Dachshund varieties, demonstrating c.544G>A segregates in other breeds of German origin. This study, in parallel with the known retinal expression and role of NECAP1 in clathrin mediated endocytosis (CME) in synapses, presents NECAP1 as a novel candidate gene for retinal degeneration in dogs and other species

Characterisation of canine KCNIP4: A novel gene for cerebellar ataxia identified by whole-genome sequencing two affected Norwegian Buhund dogs

Author summary Hereditary ataxias, which are a group of disorders characterised by incoordination of movement, are typically incurable and there are often no disease-modifying treatments available. Canine hereditary ataxias are a notable group of movement disorders in dogs, and represent well characterised naturally occurring disease models of ataxia that can help improve our understanding of the underlying biology of the disorder in both dogs and humans. We used the whole genome sequences of two affected siblings to investigate the genetic cause of a slowly progressive form of hereditary ataxia in the Norwegian Buhund dog breed, and identified a single base change within the KCNIP4 gene. We have characterised the expression of KCNIP4 in the dog, and investigated the effect of the identified mutation. This gene has not previously been implicated in inherited ataxia in any species, and our findings suggest that this and related genes represent potential candidates for ataxia in future studies in other species. Our findings will allow dog breeders to avoid producing affected dogs, reduce the disease allele frequency, and eventually eliminate the disease from the breed, through the use of a DNA test. A form of hereditary cerebellar ataxia has recently been described in the Norwegian Buhund dog breed. This study aimed to identify the genetic cause of the disease. Whole-genome sequencing of two Norwegian Buhund siblings diagnosed with progressive cerebellar ataxia was carried out, and sequences compared with 405 whole genome sequences of dogs of other breeds to filter benign common variants. Nine variants predicted to be deleterious segregated among the genomes in concordance with an autosomal recessive mode of inheritance, only one of which segregated within the breed when genotyped in additional Norwegian Buhunds. In total this variant was assessed in 802 whole genome sequences, and genotyped in an additional 505 unaffected dogs (including 146 Buhunds), and only four affected Norwegian Buhunds were homozygous for the variant. The variant identified, a T to C single nucleotide polymorphism (SNP) (NC_006585.3:g.88890674T>C), is predicted to cause a tryptophan to arginine substitution in a highly conserved region of the potassium voltage-gated channel interacting protein KCNIP4. This gene has not been implicated previously in hereditary ataxia in any species. Evaluation of KCNIP4 protein expression through western blot and immunohistochemical analysis using cerebellum tissue of affected and control dogs demonstrated that the mutation causes a dramatic reduction of KCNIP4 protein expression. The expression of alternative KCNIP4 transcripts within the canine cerebellum, and regional differences in KCNIP4 protein expression, were characterised through RT-PCR and immunohistochemistry respectively. The voltage-gated potassium channel protein KCND3 has previously been implicated in spinocerebellar ataxia, and our findings suggest that the Kv4 channel complex KCNIP accessory subunits also have an essential role in voltage-gated potassium channel function in the cerebellum and should be investigated as potential candidate genes for cerebellar ataxia in future studies in other species.Peer reviewe

Moving from information and collaboration to action: report from the 3rd International Dog Health Workshop, Paris in April 2017

Abstract Background Breed-related health problems in dogs have received increased focus over the last decade. Responsibility for causing and/or solving these problems has been variously directed towards dog breeders and kennel clubs, the veterinary profession, welfare scientists, owners, regulators, insurance companies and the media. In reality, all these stakeholders are likely to share some responsibility and optimal progress on resolving these challenges requires all key stakeholders to work together. The International Partnership for Dogs (IPFD), together with an alternating host organization, holds biennial meetings called the International Dog Health Workshops (IDHW). The Société Centrale Canine (French Kennel Club) hosted the 3rd IDHW, in Paris, in April, 2017. These meetings bring together a wide range of stakeholders in dog health, science and welfare to improve international sharing of information and resources, to provide a forum for ongoing collaboration, and to identify specific needs and actions to improve health, well-being and welfare in dogs. Results The workshop included 140 participants from 23 countries and was structured around six important issues facing those who work to improve dog health. These included individualized breed-specific strategies for health and breeding, extreme conformations, education and communication in relation to antimicrobial resistance, behavior and welfare, genetic testing and population-based evidence. A number of exciting actions were agreed during the meeting. These included setting up working groups to create tools to help breed clubs accelerate the implementation of breed-health strategies, review aspects of extreme conformation and share useful information on behavior. The meeting also heralded the development of an online resource of relevant information describing quality measures for DNA testing. A demand for more and better data and evidence was a recurring message stressed across all themes. Conclusions The meeting confirmed the benefits from inclusion of a diverse range of stakeholders who all play relevant and collaborative parts to improve future canine health. Firm actions were set for progress towards improving breed-related welfare. The next international workshop will be in the UK in 2019 and will be organized by the UK Kennel Club