Mario Capecchi and Oliver Smithies of the US and Martin Evans of Britain won the Nobel Prize for Medicine yesterday for their work in creating "knockout mice," the 21st-century testbed for biomedical research.
The trio were honored for discovering how to genetically manipulate mouse embryonic stem cells, leading to lab rodents that replicate human disease, the Nobel jury said in its citation.
Their "ground-breaking discoveries concerning embryonic stem cells and DNA recombination in mammals ... led to the creation of an immensely powerful technology," the committee said.
The discovery is technically called gene targeting but is commonly known as gene "knockout."
Engineered mice provide researchers with a lab model that yields insights into the fundamentals of diseases ranging from Alzheimer's to cancer and the response to new drugs, the jury said.
Thanks to their work, scientists can now determine the role of specific genes, a breakthrough that has "revolutionized life science," it said.
"Gene targeting in mice has pervaded all fields of biomedicine. Its impact on the understanding of gene function and its benefits to mankind will continue to increase over many years to come," it said.
To date, more than 10,000 mice genes -- approximately half of the genes in the mammalian genome -- have been knocked out.
Disabling, or knocking out, a gene is a two-step process.
The first is to snip out a functioning gene from the animal's genome, using chemical "scissors" such as an enzyme.
The next is to replace that gene with the modified one -- the gene whose flaws will cause the disease to be studied.
The big challenge is getting this introduced stretch of DNA to find the corresponding slot in the chromosome and then fit in snugly.
Little more than two decades ago, the prevailing wisdom was that the task was impossible in mammalian cells and that the DNA would insert itself in the chromosome almost randomly.
The Nobel laureates found a way to do this. In the 1980s, Evans isolated mice embryonic stem cells -- the all-purpose master cells whose manipulation could create in theory any mutation of choice.
In the meantime, Capecchi and Smithies, working independently of each other, found a way to target genes by a technique called "homologous recombination."
"Homologous" means that the introduced DNA sequence lines up with its mirror target sequence in the mouse chromosome, while "recombination" means the incoming and target sequences break and then rejoin.
"The award is very exciting and particularly appropriate," said Steve Brown, a leading scientist at the Mammalian Genetics Unit of Britain's Medical Research Council.
"Our ability to knock out -- to lose the function -- of a gene in the mouse genome has been absolutely critical in understanding the genetic basis of human disease in all areas."
The medicine prize is the first award to be announced in this year's Nobel season.
The physics prize is to be announced today followed by the chemistry prize tomorrow. The literature prize will be announced on Thursday and the peace prize on Friday.
The economics prize wraps up the season next Monday.
SPY GAMES: For more than 20 years, intelligence officers traveled to China, where they identified other MIB personnel and allegedly traded secrets for money and gifts The Taipei District Prosecutors’ Office yesterday indicted four retired Military Intelligence Bureau (MIB) officials, who are accused of providing China with a list of bureau personnel and other classified materials while attempting to recruit colleagues into a spy network in Taiwan. Prosecutors charged Chang Chao-jan (張超然), Chou Tien-tzu (周天慈) and Wang Ta-wang (王大旺), former colonels at the bureau, and Yueh Chih-chung (岳志忠) — a former major general and chief of the MIB’s Fifth Bureau, where he was in charge of sending agents to China on covert assignments — with breaches of the National Security Act (國家安全法) and the National Intelligence Services
MAKING A MOVE: Starting on Monday, short-term business travelers can apply for shorter quarantine periods, while transits of up to eight hours would be allowed The Central Epidemic Command Center (CECC) yesterday announced an easing of restrictions that would from Monday next week allow foreigners to visit or make a transit flight in Taiwan. A policy allowing short-term business travelers from countries with low or medium risks of COVID-19 infections to apply for shorter quarantine periods is also to resume that day. Minister of Health and Welfare Chen Shih-chung (陳時中), who heads the center, said that while the autumn-winter COVID-19 prevention program is to be extended after the end of this month, special conditions for foreign nationals to enter Taiwan would be restored from Monday. Foreign nationals
CONTINUED VIGILANCE: People would still be required to wear masks at eight types of public spaces and border controls would continue, Chen Shih-chung told reporters The government’s autumn-winter COVID-19 prevention program is to continue beyond Sunday, but eating and drinking on high-speed trains would be allowed from Monday, the Central Epidemic Command Center (CECC) announced yesterday. Minister of Health and Welfare Chen Shih-chung (陳時中), who heads the center, said that while there were no new confirmed cases in Taiwan yesterday, the global COVID-19 situation remains serious, so the autumn-winter COVID-19 prevention program would be extended beyond its Sunday deadline. “Border control measures, including requiring a negative polymerase chain reaction test result obtained within three days of boarding a plane to Taiwan, and undergoing quarantine in a
MORE RISK? Three Taiwanese family members were found to have the Brazilian variant, which CDC Deputy Director-General Philip Lo said might be more infectious From Wednesday, all travelers who have been in Brazil in the past 14 days are required to be quarantined at a centralized facility after arriving in Taiwan and undergo a COVID-19 test upon ending quarantine, the Central Epidemic Command Center (CECC) announced yesterday. Minister of Health and Welfare Chen Shih-chung (陳時中), who heads the center, said that starting from 12am on Wednesday, all travelers arriving from Brazil, including those who have transited through the country in the past 14 days, would have to stay at a centralized quarantine facility. “They will be tested for COVID-19 upon completing the 14-day quarantine, and they