For the Health of It
An Improved Map of the Horse Genetic Code
By University of Louisville
Researchers fill gaps in equine reference genome
to guide new approaches in fighting disease
Research led by scientists at the
University of Louisville and the
University of Kentucky has pro-
duced a more complete picture of
the domestic horse reference ge-
nome, a map researchers will use to
determine the role inherited genes
and other regions of DNA play
in many horse diseases and traits
important in equine science and
management.
By re-analyzing DNA from a
thoroughbred named Twilight, the
basis for the original horse refer-
ence genome, scientists generated
a more than ten-fold increase in
data and types of data to correct
thousands of errors in the origi-
nal sequence that was released in
2009. Since then, there have been
dramatic improvements in nucle-
otide sequencing technology and
the computational hardware and
algorithms used to analyze data. It
is now easier and less expensive to
build a reference genome.
The new equine reference ge-
nome, known as EquCab3.0, was
published today in Communica-
tions Biology, representing the
work of 21 co-authors from 14
universities and academic centers
around the world. The horse refer-
ence genome is publicly available
through the National Center for
Biotechnology Information, a di-
vision of the National Institutes of
Health.
8 • Walking On
Genome sequencing allows
researchers to read and decipher
genetic information found in DNA
and is especially important in map-
ping disease genes – discovering
diseases a horse might be genetical-
ly predisposed to developing.
Data gathered from future
genetic and genomic studies of
horses will use the new reference
as a basis, which also has implica-
tions for tackling serious diseases
in humans, said principal investi-
gator Ted Kalbfleisch, Ph.D., of the
Department of Biochemistry and
Molecular Genetics at the UofL
School of Medicine.
“Because we can sequence a
horse and map it to the reference
genome, we can know what genes
might be affected by a mutation
and come up with a hypothesis for
what went wrong,” Kalbfleisch said.
“Looking beyond the horse, we all
want to cure cancer and other dis-
eases that affect humans. Being able
to accurately generate reference
genomes gives us the tool that we
need to map an individual’s genom-
ic content. Having a high-quality
reference genome makes it possible
for us to know where an individu-
al has a mutation and personalize
therapies that will be right for an
individual and the specific disease
they have.”
Senior author James MacLeod,
V.M.D., Ph.D., of the University of
Kentucky’s Gluck Equine Research
Center added, “Increased accura-
cy of the horse reference genome
achieved through this work will
greatly facilitate additional research
in many aspects of equine science.
Medical advances for horses as a
patient population, both in terms of
sensitive diagnostic tests and emer-
gent areas of precision medicine,
are addressing critical issues for
the health and wellbeing of these
wonderful animals.”
Financial support for the re-
search was provided by the Morris
Animal Foundation, the United
States Department of Agriculture
and several additional grants to the
laboratories of individual co-au-
thors.