May 27, 2009

Scientists Complete 10-Year Mouse Genome Sequencing Effort

An international team of researchers have finished sequencing the mouse genome after a 10-year effort. Their new paper explores exactly what distinguishes our genome from that of the lab mouse, BBC News reported.

Researchers in laboratories around the world have made the tiny mouse their experimental workhorse and scientists are now confident this high-quality genome sequence will aid in the fight against human disease.

Experts say possessing a greater understanding of the genetic code of the mouse, which is about 75 percent similar to our own, could benefit the search for novel treatments for all of mankind.

Details of the work in the open-access journal PLoS Biology show the sequence comprises the full complement of genetic material in the nucleus of a cell, in what the authors say is effectively the genetic "instruction booklet" for a living animal.

While draft genome sequences have been published for the chimp, dog, rat, cat, macaque and even the duck-billed platypus, the mouse (Mus musculus) is only the second mammal after humans to have its complete genome laid bare.

However, the lab mouse is the animal most often used to better understand human illnesses and how they develop. Research carried out using mice has led to advances in the treatment of cancer, diabetes, heart disease and countless other human ailments.

The work confirmed that the mouse was an excellent experimental model for human disease, according to co-author Professor Chris Ponting from the University of Oxford.

He told BBC News the completion of the genome is extremely important in helping us to identify the genes that underpin biology that is the same across all mammals.

However, it is also important to separate the genes humans shared with mice from those which differed between them.

He said that while 75 percent of mouse genes have a single equivalent in humans, some 5,000 genes arose after the ancestors of mice and humans went their separate evolutionary ways.

Dr. Leo Goodstadt from the University of Oxford said the previous picture of the mouse genome was incomplete, in retrospect.

"Only when all the missing pieces of the genomic puzzle had been filled in did we realize that we had been missing large numbers of genes found only in mice, and not in humans," he said.

After beginning in 1999, a draft of the mouse genome sequencing effort was finally published in 2002.

Sequencing centers from the U.S. and UK estimate the cost to exceed $100 million.

However, animal experimentation has long been opposed by animal rights groups, who often campaign to ban or limit the animals used in human experiments.

The increasing growth of genetically modified (GM) animals in the UK, mainly mice, is largely responsible for a steady rise from 1997 to now in the numbers of animals used in experiments.

The complete genome could provide insights into the evolution of mammals, according to Professor Ponting of the Medical Research Council's (MRC) Functional Genomics Unit at Oxford.

He said that despite having evolved independently for the last 90 million years, humans and mice share a remarkable level of similarity.


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