Rapid development of biomedical research in the past decade has
revolutionized the research of genetic diseases. Thousands of
disease genes have been discovered in various inherited disorders
and that has resulted in the early diagnostics and prevention as
well as better treatment of the diseases. This development was
greatly boosted by the international Human Genome Project, which has
facilitated the identification of the risk alleles and disease genes
in many conditions.
Recently, the
dog’s genome has also been sequenced providing us an equally great
opportunity for many new gene discoveries. The dog is a geneticist's
dream because each pure breed represents a group of genetically
similar animals that descended from only a few ancestors. The
presence of hundreds of breeds of dog, each in an isolated breeding
population, allows us to simplify a complicated genetic problem.
Most breeds have been artificially created by man and this selective
breeding has resulted in amazing variation between breeds with
respect to weight, size, head shapes, coat, ear shape, behaviours
and diseases. Since any traits associated with a given breed must
result from a shared set of genetic determinants, these genes stand
out much more obviously than they would in a population of
unrelated, or genetically dissimilar, animals.
The large
number of reported diseases is due to the founder effect and
inbreeding practices in pure-bred dogs that uncover recessive
disease alleles. Through aggressive breeding programs man has
created over 400 different breeds of dog and burdened them with over
400 inherited diseases during the last 400 years. This places dogs
as the species with the second largest number of known genetic
diseases, surpassed only by humans. Genetic analysis of man's best
friend will also help to uncover the genes responsible for the
physical features and behaviours unique to each breed as well as the
diseases to which they are commonly susceptible, such as cancer,
epilepsy, allergies, deafness, blindness, heart disease and hip
dysplasia.
More than 60%
of canine inherited diseases are shared with humans and the coding
sequences of dogs and humans show an overall greater similarity to
each other than to mouse coding sequences. Thus, dogs can be used as
models to understand many human diseases and to develop new more
efficient and side-effect free therapies. Importantly, genetic
research in dogs is believed to facilitate the understanding of
genetic background of the common complex diseases, which have proven
difficult to crack down in human. Dogs have faithfully served man in
many duties and they are now also the best assistants of the
geneticists!
I have started
a canine genetic program in the University of Helsinki, Finland. Our
objective is to collect many breeds of dogs with different inherited
diseases and try to identify the genetic defects behind them.
Potential gene discoveries will help us to devise DNA markers and
tests, which can be used to reliably distinct affected, carrier and
healthy dogs. This will help the breed club to redesign the breeding
programs to start systemically to prevent or eradicate the disease
in the breed. This is important since it allows us to keep also the
carrier dogs in the population and develop the breed in a more
controlled way.
We have
initiated several research projects in multiple breeds of dogs in
Finland. We have started to collect pedigrees and DNA samples for
many breeds with variety of diseases such as epilepsy, autoimmune
diseases, cancers, vision disorders and behavioural problems. It is
important for the success of the projects that the owners and
breeders would participate openly and actively with the research
group to help them to get enough DNA samples, pedigree information
and clinical data to ensure necessary resources for disease gene
identification.
To be able to
conduct these studies, we need blood samples from the affected dogs
and their healthy siblings and parents as much as possible. More
samples we get, faster we can proceed. All the dog names and owner
information will not be revealed to anybody and will be handled
confidentially. Although the research group is responsible for the
major funding of the projects, we welcome also any external help.
We have also
shown recently the genetic power of dogs in epilepsy research by
cloning the first canine epilepsy gene, Epm2b (Lohi
et al. 2005), in a collection of privately owned pets,
miniature wirehaired dachshunds from the United Kingdom. A dodecamer
repeat expansion mutation was identified in the Epm2b gene, the
first example of a repeat expansion disease outside human genome.
Epilepsy
afflicts 1% of humans. Most of the epilepsy syndromes are polygenic
disorders. Epilepsy is 5-10 times more common in dogs than in human.
Currently only a few epilepsy genes has been described in human
mainly in rare large families segregating Mendelian forms of
epilepsy. Dozens of genes contributing to the common human epilepsy
syndromes still need to be identified. The high prevalence of
epilepsy in various breeds of dogs provides a great resource to
identify more causative genes, especially in common polygenic
epilepsies. Identified canine loci can be directly tested in
collections of human epilepsy patients to expedite human gene
cloning. This type of research will help both canine and human
health in epilepsy and many other common diseases.
We wish an
open and fruitful collaboration with all dog owners, breeders and
friends, and welcome as many sample as you can contribute for the
projects. Together we can now start to advance the healthiness of
our breeds and make sure we have happy dogs in future!
If you want to
participate in this research, please email
hannes.lohi@helsinki.fi
Tämä sähköpostiosoite on suojattu
roskapostia vastaan, aseta javascripttuki päälle nähdäksesi
osoitteen.
for more information.
Hannes Lohi,
PhD, Docent
Academy Research Fellow
Biomedicum Helsinki
University of Helsinki and Folkhälsan Institute of Genetics
Blood samples:
Instructions
for blood sample collection can be found
here. The sample form is also
available from
this link.

Questionnaires:
Disease
questionnaires available in English at this time are
epilepsy questionnaire
(more information about epilepsy research
here)
and
missing teeth questionnaire.
News in
English
Academy of Finland Award to Hannes Lohi