Imputation of canine genotype array data using 365 whole-genome sequences improves power of genome-wide association studies.

Genomic resources for the domestic dog have improved with the widespread adoption of a 173k SNP array platform and updated reference genome. SNP arrays of this density are sufficient for detecting genetic associations within breeds but are underpowered for finding associations across multiple breeds or in mixed-breed dogs, where linkage disequilibrium rapidly decays between markers, even though such studies would hold particular promise for mapping complex diseases and traits. Here we introduce an imputation reference panel, consisting of 365 diverse, whole-genome sequenced dogs and wolves, which increases the number of markers that can be queried in genome-wide association studies approximately 130-fold. Using previously genotyped dogs, we show the utility of this reference panel in identifying potentially novel associations, including a locus on CFA20 significantly associated with cranial cruciate ligament disease, and fine-mapping for canine body size and blood phenotypes, even when causal loci are not in strong linkage disequilibrium with any single array marker. This reference panel resource will improve future genome-wide association studies for canine complex diseases and other phenotypes.

Genetic structure in village dogs reveals a Central Asian domestication origin.

Dogs were the first domesticated species, originating at least 15,000 y ago from Eurasian gray wolves. Dogs today consist primarily of two specialized groups--a diverse set of nearly 400 pure breeds and a far more populous group of free-ranging animals adapted to a human commensal lifestyle (village dogs). Village dogs are more genetically diverse and geographically widespread than purebred dogs making them vital for unraveling dog population history. Using a semicustom 185,805-marker genotyping array, we conducted a large-scale survey of autosomal, mitochondrial, and Y chromosome diversity in 4,676 purebred dogs from 161 breeds and 549 village dogs from 38 countries. Geographic structure shows both isolation and gene flow have shaped genetic diversity in village dog populations. Some populations (notably those in the Neotropics and the South Pacific) are almost completely derived from European stock, whereas others are clearly admixed between indigenous and European dogs. Importantly, many populations--including those of Vietnam, India, and Egypt-show minimal evidence of European admixture. These populations exhibit a clear gradient of short--range linkage disequilibrium consistent with a Central Asian domestication origin.

Genomic analysis establishes correlation between growth and laryngeal neuropathy in Thoroughbreds.

BACKGROUND: Equine recurrent laryngeal neuropathy (RLN) is a bilateral mononeuropathy with an unknown pathogenesis that significantly affects performance in Thoroughbreds. A genetic contribution to the pathogenesis of RLN is suggested by the higher prevalence of the condition in offspring of RLN-affected than unaffected stallions. To better understand RLN pathogenesis and its genetic basis, we performed a genome-wide association (GWAS) of 282 RLN-affected and 268 control Thoroughbreds. RESULTS: We found a significant association of RLN with the LCORL/NCAPG locus on ECA3 previously shown to affect body size in horses. Using height at the withers of 505 of these horses, we confirmed the strong association of this locus with body size, and demonstrated a significant phenotypic and genetic correlation between height and RLN grade in this cohort. Secondary genetic associations for RLN on ECA18 and X did not correlate with withers height in our cohort, but did contain candidate genes likely influencing muscle physiology and growth: myostatin (MSTN) and integral membrane protein 2A (ITM2A). CONCLUSIONS: This linkage between body size and RLN suggests that selective breeding to reduce RLN prevalence would likely reduce adult size in this population. However, our results do not preclude the possibility of modifier loci that attenuate RLN risk without reducing size or performance, or that the RLN risk allele is distinct but tightly linked to the body size locus on ECA3. This study is both the largest body size GWAS and the largest RLN GWAS within Thoroughbred horses to date, and suggests that improved understanding of the relationship between genetics, equine growth rate, and RLN prevalence may significantly advance our understanding and management of this disease.

A simple genetic architecture underlies morphological variation in dogs.

Domestic dogs exhibit tremendous phenotypic diversity, including a greater variation in body size than any other terrestrial mammal. Here, we generate a high density map of canine genetic variation by genotyping 915 dogs from 80 domestic dog breeds, 83 wild canids, and 10 outbred African shelter dogs across 60,968 single-nucleotide polymorphisms (SNPs). Coupling this genomic resource with external measurements from breed standards and individuals as well as skeletal measurements from museum specimens, we identify 51 regions of the dog genome associated with phenotypic variation among breeds in 57 traits. The complex traits include average breed body size and external body dimensions and cranial, dental, and long bone shape and size with and without allometric scaling. In contrast to the results from association mapping of quantitative traits in humans and domesticated plants, we find that across dog breeds, a small number of quantitative trait loci (< or = 3) explain the majority of phenotypic variation for most of the traits we studied. In addition, many genomic regions show signatures of recent selection, with most of the highly differentiated regions being associated with breed-defining traits such as body size, coat characteristics, and ear floppiness. Our results demonstrate the efficacy of mapping multiple traits in the domestic dog using a database of genotyped individuals and highlight the important role human-directed selection has played in altering the genetic architecture of key traits in this important species.

Banking on the Last Gift: Cornell's Signature Program of Postmortem Tissue Procurement.

High-quality, well-annotated, healthy tissue specimens are crucial to the success of basic and translational research, but often difficult to procure. Postmortem (PM) tissue collections provide the opportunity to collect these healthy biospecimens. PM procurement programs led by biobanks can further contribute by providing researchers with rare biospecimens collected with short postmortem intervals (PMI) in controlled environments. To support biomedical and translational research, the Cornell Veterinary Biobank (CVB), an ISO 20387 accredited core resource at the Cornell University College of Veterinary Medicine, has performed PM tissue collections from research and privately owned animals since 2013. The CVB PM collection team, consisting of a board-certified veterinary pathologist, a licensed veterinary technician collection specialist, and a data capture specialist, performs rapid tissue collections during controlled warm necropsies, with an accepted PMI of ≤2 hours and a target PMI of ≤1 hour. A retrospective analysis of PM collections between 2013 and 2020 was completed, consisting of 4077 aliquots of 1582 biospecimens from 69 donors (48 canine, 16 feline, and 5 equine). An average of 22.93 biospecimens per donor were collected (range: 1-49). The average PMI for standard collections was 43.48 ± 2.30 minutes, starting on average 20.81 ± 1.61 minutes after time of death. Thus far, the CVB has a favorable utilization rate, with 414 aliquots (10.15%) from 350 specimens (20.12%) and 45 animals (65.22%) distributed to researchers. The success of the CVB PM tissue biobanking program, collecting high-quality biospecimens with short PMIs, was due to support from veterinary pathologists, the competence of CVB personnel, and the continuous evolution of methods within a quality management system. Improvement of PM tissue collection programs in biobanks, with standardized practices for all processes and specialized personnel, can enhance the quality and increase utilization of its biospecimens and associated data.

Complex population structure in African village dogs and its implications for inferring dog domestication history.

High genetic diversity of East Asian village dogs has recently been used to argue for an East Asian origin of the domestic dog. However, global village dog genetic diversity and the extent to which semiferal village dogs represent distinct, indigenous populations instead of admixtures of various dog breeds has not been quantified. Understanding these issues is critical to properly reconstructing the timing, number, and locations of dog domestication. To address these questions, we sampled 318 village dogs from 7 regions in Egypt, Uganda, and Namibia, measuring genetic diversity >680 bp of the mitochondrial D-loop, 300 SNPs, and 89 microsatellite markers. We also analyzed breed dogs, including putatively African breeds (Afghan hounds, Basenjis, Pharaoh hounds, Rhodesian ridgebacks, and Salukis), Puerto Rican street dogs, and mixed breed dogs from the United States. Village dogs from most African regions appear genetically distinct from non-native breed and mixed-breed dogs, although some individuals cluster genetically with Puerto Rican dogs or United States breed mixes instead of with neighboring village dogs. Thus, African village dogs are a mosaic of indigenous dogs descended from early migrants to Africa, and non-native, breed-admixed individuals. Among putatively African breeds, Pharaoh hounds, and Rhodesian ridgebacks clustered with non-native rather than indigenous African dogs, suggesting they have predominantly non-African origins. Surprisingly, we find similar mtDNA haplotype diversity in African and East Asian village dogs, potentially calling into question the hypothesis of an East Asian origin for dog domestication.

Purpose, Partnership, and Possibilities: The Implementation of the Dog Aging Project Biobank.

Background: Biobanks have been supporting longitudinal prospective and retrospective studies by providing standardized services for the acquisition, transport, processing, storage, and distribution of high-quality biological material and associated data. Here, we describe how the Dog Aging Project (DAP), a large-scale longitudinal study of the domestic dog (Canis familiaris) with translational applications for humans, developed a biobank of canine biospecimens and associated data. Design and methods: This was accomplished by working with the Cornell Veterinary Biobank, the first biobank in the world to receive accreditation to ISO 20387:2018-General Requirements for Biobanking. The biobank research team was involved in the early collection stages of the DAP, contributing to the development of appropriate workflows and processing fit-for-purpose biospecimens. In support of a dynamic strategy for real-time adjustment of processes, a pilot phase was implemented to develop, test, and optimize the biospecimen workflows, followed by an early phase of collection, processing, and banking of specimens from DAP participants. Results: During the pilot and early phases of collection, the DAP Biobank stored 164 aliquots of whole blood, 273 aliquots of peripheral blood mononuclear cells, 130 aliquots of plasma, and 70 aliquots of serum, and extracted high molecular weight genomic DNA suitable for whole-genome sequencing from 109 whole blood specimens. These specimens, along with their associated preanalytical data, have been made available for distribution to researchers. Conclusion: We discuss the challenges and opportunities encountered during the implementation of the DAP Biobank, along with novel strategies for promoting biobanking sustainability such as partnering with a DAP quality assurance manager and a DAP marketing and communication specialist and developing a pilot grant structure to fund small innovative research projects.

A genome-wide association study to investigate genetic loci associated with primary glaucoma in American Cocker Spaniels.

OBJECTIVE: To identify genetic associations with primary glaucoma (PG) in American Cocker Spaniels using a genome-wide association study (GWAS). ANIMALS: A nationwide ambidirectional case-control cohort study was performed in American Cocker Spaniels that had an ophthalmic examination performed by a veterinarian. Ninety-four dogs with PG (cases) and 111 dogs without glaucoma (controls) met phenotypic criteria and had a blood sample collected after receiving informed owner consent. PROCEDURES: Genomic DNA was extracted from whole blood samples and genotyped (CanineHD BeadChip, Illumina Inc). A case-control GWAS using a linear mixed model was performed, and 3 significance thresholds were calculated (1) using a Bonferroni correction on all single nucleotide polymorphisms (SNPs) included in the GWAS, (2) using a Bonferroni correction on only the unlinked SNPs from a pruned data set, and (3) using 10,000 random phenotype permutations. RESULTS: Following genotype data quality control, 89 cases and 93 controls were included in the GWAS. We identified an association on canine chromosome (CFA10); however, it did not reach statistical significance. Potential candidate genes within the surrounding linkage disequilibrium interval include coiled-coil domain containing 85A (CCDC85A) and extracellular growth factor containing fibulin extracellular matrix protein 1 (EFEMP1). CLINICAL RELEVANCE: Primary glaucoma in the American Cocker Spaniel is a complex heterogeneous disease that may be influenced by a locus on CFA10. The candidate genes CCDC85A and EFEMP1 within the identified linkage disequilibrium interval have been shown to be involved in human open-angle glaucoma.

Complex Feline Disease Mapping Using a Dense Genotyping Array.

The current feline genotyping array of 63 k single nucleotide polymorphisms has proven its utility for mapping within breeds, and its use has led to the identification of variants associated with Mendelian traits in purebred cats. However, compared to single gene disorders, association studies of complex diseases, especially with the inclusion of random bred cats with relatively low linkage disequilibrium, require a denser genotyping array and an increased sample size to provide statistically significant associations. Here, we undertook a multi-breed study of 1,122 cats, most of which were admitted and phenotyped for nine common complex feline diseases at the Cornell University Hospital for Animals. Using a proprietary 340 k single nucleotide polymorphism mapping array, we identified significant genome-wide associations with hyperthyroidism, diabetes mellitus, and eosinophilic keratoconjunctivitis. These results provide genomic locations for variant discovery and candidate gene screening for these important complex feline diseases, which are relevant not only to feline health, but also to the development of disease models for comparative studies.

A Biobank's Journey: Implementation of a Quality Management System and Accreditation to ISO 20387.

Biobanks play an integral role in research and precision medicine by acquiring, processing, storing, and distributing high-quality, clinically annotated biological material. Compliance with biobanking standards and the implementation of quality management systems (QMS) can improve the quality of the biological material and associated data (BMaD). By undergoing third-party assessments, biobanks can demonstrate compliance to these standards and instill confidence in their users. In the 8 months following the publication of the International Organization for Standardization (ISO) 20387:2018 General Requirements for Biobanking standard, the Cornell Veterinary Biobank (CVB) became compliant with the standard requirements, including developing and implementing a QMS. This was achieved through the documentation of all biobanking processes, demonstration of personnel competence, the stringent control of documents and records, and ongoing evaluation of processes and the QMS. Procedures describing the control of documents and records were implemented first to provide a foundation on which to build the QMS, followed by procedures for documenting the identification of risks and opportunities, improvements, and corrective actions following nonconforming outputs. Internal audit and management review programs were developed to verify QMS performance and to monitor quality objectives. Procedures for the governance and management of the biobank were developed, including the following: organizational structure; confidentiality and impartiality policies; facility and equipment maintenance, calibration, and monitoring; personnel training and competency; and evaluation of external providers. All processes on scope were described, along with the validation and verification of methods, to ensure the fitness-for-purpose of the BMaD and the reproducibility of biobanking processes. Training sessions were held during implementation of the QMS to ensure all personnel would conform to the procedures. In April 2019, the CVB underwent third-party assessment by the American Association of Laboratory Accreditation (A2LA) and became the first biobank in the world to receive accreditation to ISO 20387:2018.

Comparison and Analysis of Two Internationally Recognized Biobanking Standards.

Impactful biobanking is underpinned by quality assurance and standardization. Several general biobank standards exist that can be associated with programs to provide different levels of conformity assessment, including the Canadian Tissue Repository Network (CTRNet) Certification program and the International Organization for Standardization (ISO) 20387 and accreditation bodies. We examined the CTRNet Required Operational Practices (2017) and ISO 20387 (2018), to compare them. Although the organization of each standard is different, both describe a set of discrete requirements (elements or subclauses) that comprise the standards that are contained in sections called chapters (CTRNet) or clauses (ISO). The standards have a similar number of requirements (CTRNet: 362, ISO: 322). To compare these standards, we reclassified the requirements in the ISO standard into 13 categories based on a combination of the chapter headings used in the ISBER and NCI Best Practices that represent important areas of biobanking activity. This categorization of requirements showed that each standard has a different emphasis reflected in different densities of requirements within distinct areas of biobanking. The ISO standard emphasizes Quality Management Systems whereas the CTRNet standard has an even coverage across the full spectrum of biobanking areas, including activities that are relevant to participant enrollment. Nevertheless, ∼60% of the requirements in the CTRNet standard match with those of the ISO standard. We conclude that these two standards have much in common but recommend that individual biobanks consider each standard carefully in the context of the purpose, focus, scale, and scope of their biobank to determine the appropriate standard to be followed.

Biobanking in the COVID-19 Era and Beyond: Part 2. A Set of Tool Implementation Case Studies.

The COVID-19 era has brought about a number of novel challenges for the global biobanking community. An array of diverse tools (e.g., standards, best practices, and plans) exists to support quality and fitness-for-purpose in biobank operations. The International Society for Biological and Environmental Repositories (ISBER) COVID-19 Response Task Force has set out to identify needs and gaps in these tools and make recommendations for the next generation of available tools, having closely examined the COVID-19-related challenges. While conducting this work to examine the relationships between tools and biobank adaptability, a subgroup of the task force conducted a parallel effort to develop and describe individual COVID-19 era case studies based on a number of operating biobanks. Each case study presents a different combination of implemented tools. Observations and lessons learned from these case studies are provided, and experiences with tool implementation are discussed. This information is supplemented by data relating to tool usefulness that was obtained through an ISBER survey discussed in a companion article. The knowledge gained from this study will be combined with other task force efforts to make recommendations to better position the biobanking community in their response to future emergencies.

Biobanking in the COVID-19 Era and Beyond: Part 1. How Early Experiences Can Translate into Actionable Wisdom.

The era of COVID-19 has brought about a number of novel challenges for the global biobanking community. To better position the biobanking community to cope with current and future challenges, the International Society for Biological and Environmental Repositories (ISBER) COVID-19 Response Task Force was convened to identify needs and gaps in biobanking tools (existing resources that support good practice), for example, standards, best practices, business, etc. and to make recommendations to benefit the community. Toward these goals, the Task Force assembled a set of questions to explore individual biobanks' experiences, with emphasis on identification of key challenges and approaches, including tools employed. A survey was designed with the use of these questions and administered by ISBER. This article presents a summary of the aggregated data obtained from the survey responses, illustrating some of the major issues encountered and identifying which tools the survey respondents found most useful. In particular, this article focuses on the challenges identified during the early months of the COVID-19 era. Recommendations are provided to support biobank emergency preparedness for the future, address lessons learned, and propose solutions to bridge identified gaps. The analysis and the complete survey dataset will also inform the larger Task Force goal to develop specific tool recommendations.

Development and use of DNA archives at veterinary teaching hospitals to investigate the genetic basis of disease in dogs.

The DNA archives developed at veterinary medical teaching hospitals will be important resources for mapping disease loci and identifying underlying genes. The most important feature of a DNA archive is accurate identification or exclusion of diseases in each animal. Such archives will be complimentary resources to tissue banks that are currently available.

Genetic mapping of distal femoral, stifle, and tibial radiographic morphology in dogs with cranial cruciate ligament disease.

Cranial cruciate ligament disease (CCLD) is a complex trait. Ten measurements were made on orthogonal distal pelvic limb radiographs of 161 pure and mixed breed dogs with, and 55 without, cranial cruciate partial or complete ligament rupture. Dogs with CCLD had significantly smaller infrapatellar fat pad width, higher average tibial plateau angle, and were heavier than control dogs. The first PC weightings captured the overall size of the dog's stifle and PC2 weightings reflected an increasing tibial plateau angle coupled with a smaller fat pad width. Of these dogs, 175 were genotyped, and 144,509 polymorphisms were used in a genome-wide association study with both a mixed linear and a multi-locus model. For both models, significant (pgenome <3.46×10-7 for the mixed and< 6.9x10-8 for the multilocus model) associations were found for PC1, tibial diaphyseal length and width, fat pad base length, and femoral and tibial condyle width at LCORL, a known body size-regulating locus. Other body size loci with significant associations were growth hormone 1 (GH1), which was associated with the length of the fat pad base and the width of the tibial diaphysis, and a region on CFAX near IRS4 and ACSL4 in the multilocus model. The tibial plateau angle was associated significantly with a locus on CFA10 in the linear mixed model with nearest candidate genes BET1 and MYH9 and on CFA08 near candidate genes WDHD1 and GCH1. MYH9 has a major role in osteoclastogenesis. Our study indicated that tibial plateau slope is associated with CCLD and a compressed infrapatellar fat pad, a surrogate for stifle osteoarthritis. Because of the association between tibial plateau slope and CCLD, and pending independent validation, these candidate genes for tibial plateau slope may be tested in breeds susceptible to CCLD before they develop disease or are bred.

Gene expression in hip soft tissues in incipient canine hip dysplasia and osteoarthritis.

Canine hip dysplasia and developmental dysplasia of the human hip share demographic, phenotypic, and clinical features including the predisposition to develop osteoarthritis in affected joints. To support the results of genetic mapping studies for CHD and its concomitant osteoarthritis with functional information, we performed RNA-seq on hip capsule and teres ligament of affected and unaffected dogs. RNA seq showed that expressed genes segregated according age, capsule or ligament, and hip phenotype. Expression of HHIP, DACT2, and WIF1 was significantly higher in capsule from control hips than dysplastic hips indicating a disruption of the hedgehog signaling pathway. Expression of SPON 1, a key component of the WNT pathway, was increased significantly in both dysplastic capsule and ligament while FBN2 and EMILIN3 were significantly increased in dysplastic capsule. Of genes associated with human hip osteoarthritis, expression of ACAN, IGF1, CILP2, COL11A1, COL8A1, and HAPLN was increased significantly in dysplastic capsule. The significant increase in expression of PLA2F, TNFRSF, TMEM, and IGFBP in dysplastic capsule indicated an injury response. Gene set enrichment analysis revealed that genes involved in extracellular matrix structure, epithelial to mesenchymal transition, myogenesis, growth factor signaling, cancer and immune pathways were enriched in dysplastic capsule. For teres ligament from dysplastic joints, genes in retinoic signaling pathways and those encoding extracellular matrix molecules, but not proteoglycans, were enriched. Hip tissues respond to abnormal mechanics early in dysplastic hip development and these pathways present targets for intervention in the early synovitis and capsulitis secondary to canine and human hip dysplasia. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:313-324, 2019.

Complex disease and phenotype mapping in the domestic dog.

The domestic dog is becoming an increasingly valuable model species in medical genetics, showing particular promise to advance our understanding of cancer and orthopaedic disease. Here we undertake the largest canine genome-wide association study to date, with a panel of over 4,200 dogs genotyped at 180,000 markers, to accelerate mapping efforts. For complex diseases, we identify loci significantly associated with hip dysplasia, elbow dysplasia, idiopathic epilepsy, lymphoma, mast cell tumour and granulomatous colitis; for morphological traits, we report three novel quantitative trait loci that influence body size and one that influences fur length and shedding. Using simulation studies, we show that modestly larger sample sizes and denser marker sets will be sufficient to identify most moderate- to large-effect complex disease loci. This proposed design will enable efficient mapping of canine complex diseases, most of which have human homologues, using far fewer samples than required in human studies.