AKC Canine Health Foundation - 27

My Perspectives on Canine Genetic Research - Past,
Present, and Future; History of Genetic Tests Featuring the
OFA
Keynote: 2023 Asa Mays, DVM Award Recipient
Gary Johnson, DVM, PhD
University of Missouri
With remarks by Eddie Dziuk, MBA
Orthopedic Foundation for Animals
BIOGRAPHY
Dr. Gary S. Johnson received a BA degree in Chemistry from Augsburg College in 1966 and a
PhD degree in Biochemistry from Kansas State University in 1971. Next, he did postdoctoral
studies at Johns Hopkins University. From there, he entered Veterinary School and received a
DVM from the University of Minnesota in 1977. He then did postdoctoral studies on canine
bleeding disorders at the New York State Department of Health. In 1980, he began a career as
in independent investigator in what was then the Department of Veterinary Pathology in the
College of Veterinary Medicine at the University of Missouri. For the first ten years, his research
focused on von Willebrand factor and other proteins involved in platelet function and blood
coagulation. In the early 1990s, the advent of DNA amplification by the polymerase chain
reaction provided access to DNA studies for investigators with training in biochemistry. This
enabled Dr. Johnson to begin searching for mutations responsible for a wide variety of heritable
diseases in domestic animals. The first causal mutation identified in Dr. Johnson's laboratory
was a termination codon mutation in FECH, the gene that encodes ferrochelatase. This
mutation caused protoporphyria in Limousin cattle. The second identified causal mutation was a
CLN8 missense mutation that caused neuronal ceroid lipofuscinosis, a lysosomal storage
disease subtype, in English Setters. Ten years ago, Dr. Johnson and colleagues were among
the first to use whole genome sequencing to identify mutations responsible for heritable canine
diseases. They have used this technology to identify the molecular genetic causes for a wide
variety of heritable canine diseases. Dr. Johnson is nearing the end of his career; however, a
generous gift from the Orthopedic Foundation for Animals ensures that canine moleculargenetic
research will continue at the University of Missouri College of Veterinary Medicine for
the foreseeable future.
PRESENTATION ABSTRACT
Over 30 years ago, when I learned how to amplify and sequence small segments of DNA by the
polymerase chain reaction, I focused my research on canine molecular genetics. At that time,
few if any canine genes had been sequenced. Over the years the technology and resources
improved to where we now routinely use whole-genome sequencing of individual dogs. This has
resulted in the discovery of numerous disease-causing mutations.
Currently, we continue to use whole-genome sequencing to discover novel causes for heritable
canine diseases. In addition, we are conducting AKC Canine Health Foundation supported
research to better understand the pathogenesis and epidemiology of canine degenerative
myelopathy, a fatal neurodegenerative disease. This disease is very common with over 5% of
canine chromosomes carrying the degenerative-myelopathy-associated mutation. Yet, because
the ages-at-onset for degenerative myelopathy overlap a dog's life expectancy, many dogs with
the genetic predisposition for degenerative myelopathy die from other causes. This complicates
cost-to-benefit decisions about DNA testing. We are analyzing online-survey results from
2023 National Parent Club Canine Health Conference
Presented by the AKC Canine Health Foundation and Nestlé Purina PetCare

AKC Canine Health Foundation

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