Scientists unveiled a rough draft of the dog genome last week, data that will help identify the genes involved in canine disorders, as well as shedding light on human diseases such as cancer, epilepsy and narcolepsy. The dog DNA sequence, published in Science last week, is freely available, although it is not yet complete. 'We have a lot of fragments' says team leader Ewen Kirkness of the Institute for Genomic Research in Rockville, Maryland. But a rough survey can still provide a lot of results, says US genome researcher William Murphy, and the technique could be extended to other species that don't merit a full genome project.
The dog now famous for having its entire genetic code deciphered is Shadow, a male poodle belonging to Craig Venter. 'Shadow is now one of history's most valuable dogs' said Venter, whose own DNA sequence was published by his firm Celera Genomics in 2001. Analysis of the human and dog genomes reveals that 18,473 of the estimated 24,567 dog genes have human equivalents, compared to 18,311 genes shared between mice and humans. The dog genome sequence is made up of around 2.4 billion DNA base-pairs, or 'letters', whereas humans have around 2.9 billion. These results show that humans and dogs are much closer to each other in evolutionary terms than they are to mice.
The researchers say that their results will be useful for dog owners and breeders, as they will enable the identification of genes involved in over 350 dog diseases. Studying genetic variation in dogs could also reveal why some breeds are much better at hearing, or what gives others their acute sense of smell. Dog geneticist Gregory Acland, of Cornell University, also points out that most human diseases have human counterparts, and that 'dogs are closer to humans in size, lifestyle and lifespan than rodents'. He has already used Shadow's sequence in his work on eye disease, reports Nature magazine.