The Gene Scene

The question 'What are you - a man or a mouse?' has been answered by science. Pet owners will be delighted to know that they are more closely related to dogs than to mice.

After studying 80% the dog genome, the Institute for Genomic Research in Maryland, has determined that dogs and humans share almost 19,000 genes and from this, that dogs are more closely related to humans than the mouse is. Considering that humans have around 30,000 genes, perhaps the dog is no longer 'Man's best friend' but more 'Man's close relative'.  No wonder we love our pooches.

Indeed, the dog could be come man's very-best-and-most-valuable-friend because many canine diseases have human equivalents and studying the canine genetic map could therefore lead to better treatment of human diseases.

What is Gene Mapping?

The science is based on gene mapping. Gene mapping is where the location of each gene in a species' chromosomes is determined.  The collection of genes and chromosomes that are specific for any particular species is known as its genome. Thus, the human genome is made up of approximately 30,000 genes.

Why is gene mapping important?

Gene mapping is important for disease control. By mapping genes, inherited diseases, for instance, could be better understood and thereby controlled.

Taking cancer as an example, it occurs when the DNA in a single cell changes. This change is often called a mutation. If this DNA mutation occurs in a sensitive location on a gene, the cell that contains that gene may grow out of control. It copies itself many times over and cancer tissue is thus formed.

In individuals of any species, cancer-causing genes can be present at birth. If scientists can find the genes that contain the mutations which lead to cancer, then cancer treatment can be revolutionised.

Gene mapping could help to identify individual lines of dogs within a breed that carry cancer-causing genes and breeders could choose not to breed with such dogs. In the same way, humans with gene-borne diseases are being identified.

Gene mapping could help to identify individual lines of dogs within a breed that carry cancer-causing genes.

Over the last twenty years, genes in humans associated with the hereditary diseases cystic fibrosis, some forms of haemophilia, muscular dystrophy, and Huntington's disease have been discovered. Each of these diseases is caused by defects in single genes.  Other diseases are caused by defects in several genes and studying such diseases is much more complex.  Therefore mapping the human and the canine genome, where each gene is clearly identified and understood, will make the control of complex, genetically-based diseases much more successful in both species.

The Human Genome Project

The Humane Genome Project is an international scientific collaboration, the goal of which is to gain a basic understanding of the entire genetic blueprint of human beings.

On the 14th April this year, the successful completion of this project was announced at a cost of over 150 million pounds. This was two years ahead of schedule.

Already, as a result, new genes involved in diseases such as diabetes, leukaemia, eczema and many other human diseases have been discovered.

The Dog Genome Project

The Dog Genome Project is a collaborative study involving scientists at the University of California, the University of Oregon, and the Fred Hutchinson Cancer Research Center.

Its aim is to produce a genetic map of all dog chromosomes and thereby to map the genes that cause disease in dogs and control the appearance and affect behaviour of dog breeds.

There is a huge variation in dog breeds. Consider that a two kilogram Chihuahua and a 100 kilogram Saint Bernard are identical species - they are all Canis familiaris - the domestic dog.  Consider further that the creation of such variation has occurred over such a small evolutionary time span and, further, that it has mostly been driven by the needs and actions of humans. This variation in appearance and behaviour exceeds that of any other species on earth and makes the analysis of the canine genome a fascinating scientific endeavour.  

Dog genetics offers the hope of discovering the genetic basis behind the development and behaviour of many mammalian species.

One major goal of the dog genome project is to develop a map of the genes causing inherited diseases in dogs. It is widely recognized that in many pedigreed dog lines, diseases such as cancer, epilepsy and skeletal malformations, amongst others, run in families.

Where mapping the human genome has led to rapid treatment of human disease, a map of the dog genome will cause similar advances in veterinary medicine. The map will allow the development of more effective breeding practices to eliminate many genetic diseases from certain breeds of dogs but further will certainly help in our understanding of the treatment of many diseases in humans.  So that proves it - dogs are man's best friend.

Follow these links for more information:

Dog Genome Project

Canine Genomic Research

What is the canine genome?

News release NC State University