The rat is the third mammalian DNA sequence to be deciphered, following the human and mouse genomes. Sequencing it was a priority for researchers, due to the widespread use of rats in medical research, reports Cordis News.
The sequence itself, published in the journal Nature, is made up of some 25,000 genes, 90 per cent of which have a match in the human and mouse models. This means that nearly all disease-related human genes have a counterpart in the rat, which should ensure better rat models for researching human diseases and provide new targets for treatments.
The rat genome was documented by combining methods from the human and mouse genome project to produce a highly accurate sequence. 'This makes it more efficient and thorough than previous genome sequences,' said Richard Gibbs from Baylor College of Medicine in Houston, in the US, who coordinated the international sequencing effort. Teams from various institutes in the UK, Germany and Sweden were involved in the project.
The sequencing effort has already led to some interesting discoveries. For example, rats have more genes designed to break down toxins than humans do, which could have consequences for drugs testing. If indeed rats are better able to break down toxins than humans, then researchers will have to re-evaluate the practice of using rats in toxicity tests for human drugs.
In an effort to gain further insights into evolution, Dr Gibbs and his colleagues will now turn their attention towards sequencing the genomes of the cow, macaque monkey and sea urchin.
Groups in the US and Japan are also trying to sequence the genome of the chimpanzee, another commonly used animal for medical research.