Tomas Lindahl and Paul Modrich and Aziz Sancar were named as the winners on Wednesday morning at a news conference in Stockholm, Sweden.
Their work uncovered the mechanisms used by cells to repair damaged DNA - a fundamental process in living cells and important in cancer.
Prof Lindahl is Swedish, but has worked in the UK for more than three decades.
The prize money of eight million Swedish kronor (£634,000; $970,000) will be shared among the winners.
"It was a surprise. I know that over the years I've occasionally been considered for a prize, but so have hundreds of other people. I feel lucky and proud to be selected today," Tomas Lindahl, from the UK's Francis Crick Institute, told journalists.
DNA is open to an onslaught of different phenomena that can generate defects in our genomes.
UV radiation and molecules known as free radicals can cause damage. Furthermore, defects can arise when DNA is copied during cell division - a process that occurs millions of times each day in our bodies.
"Cigarette smoke contains small reactive chemicals, which bind to the DNA and prevent it from being replicated properly - so they are mutagens. And once there is damage in the DNA this can cause diseases including cancer," said Prof Lindahl, who for 20 years ran the Clare Hall laboratories in Hertfordshire - now part of Cancer Research UK.
Image copyrightReutersImage captionLindahl, Modrich and Sancar join 168 previous winners of the chemistry Nobel since 1901
In the 1970s, scientists had thought that DNA was a stable molecule, but Prof Lindahl demonstrated that it decays at a surprisingly fast rate.
This led him to discover a mechanism called base excision repair, which perpetually counteracts the degradation of DNA.
Sir Martyn Poliakoff, vice president of the UK's Royal Society, said: "Understanding the ways in which DNA repairs itself is fundamental to our understanding of inherited genetic disorders and of diseases like cancer.
Turkish-born biochemist Aziz Sancar, professor at the University of North Carolina, Chapel Hill, US, uncovered a different DNA mending process called nucleotide excision repair. This is the mechanism cells use to repair damage to DNA from UV light - but it can also undo genetic defects caused in other ways.
The American Paul Modrich, professor of biochemistry at Duke University in North Carolina, demonstrated how cells correct flaws that occur as DNA is copied when cells divide. This mechanism, called mismatch repair, results in a 1,000-fold reduction in the error frequency when DNA is replicated.
NEUTRINO FLIP
The discovery that neutrinos switch between different "flavours" has won the 2015 Nobel Prize in physics.
Neutrinos are ubiquitous subatomic particles with almost no mass and which rarely interact with anything else, making them very difficult to study.
Takaaki Kajita and Arthur McDonald led two teams which made key observations of the particles inside big underground instruments in Japan and Canada.
They were named on Tuesday morning at a news conference in Stockholm, Sweden.
Goran Hansson, secretary general of the Royal Swedish Academy of Sciences, which decides on the award, declared: "This year's prize is about changes of identity among some of the most abundant inhabitants of the Universe."
Telephoning Prof McDonald from the conference, he said: "Good morning again - I'm the guy who woke you up about 45 minutes ago."
Prof McDonald was in Canada, where he is a professor of particle physics at Queen's University in Kingston. He said hearing the news was "a very daunting experience".
"Fortunately, I have many colleagues as well, who share this prize with me," he added. "[It's] a tremendous amount of work that they have done to accomplish this measurement.
"We have been able to add to the world's knowledge at a very fundamental level."
Prof Kajita, from the University of Tokyo, described the win as "kind of unbelievable". He said he thought his work was important because it had contradicted previous assumptions.
"I think the significance is - clearly there is physics that is beyond the Standard Model."
ABOUT NEUTRINOS
Second most abundant particle in the Universe, after photons of light
Means 'small neutral one' in Italian; was first proposed by Wolfgang Pauli in 1930
Uncharged, and created in nuclear reactions and some radioactive decay chains
Shown to have a tiny mass, but hardly interacts with other particles of matter
Comes in three flavours, or types, referred to as muon, tau and electron
These flavours are able to oscillate - flip from one type to another - during flight
In the late 1990s, physicists were faced with a mystery: all their Earth-based detectors were picking out far fewer neutrinos than theoretical models predicted - based on how many should be produced by distant nuclear reactions, from our own Sun to far-flung supernovas.
Those detectors mostly entail huge volumes of fluid, buried deep underground to avoid interference. When such a vast space is littered with light detectors, neutrinos can be glimpsed because of the tiny flashes of light that occur when they - very occasionally - bump into an atom.
They include the Super-Kamiokande detector beneath Japan's Mount Kamioka, where Prof Kajita still works, and the Sudbury Neutrino Observatory in Ontario, Canada, run by Prof McDonald. Both are housed in mines.
Shape shifters
In 1998, Prof Kajita's team reported that neutrinos they had caught, bouncing out of collisions in the Earth's atmosphere, had switched identity: they were a different "flavour" from what those collisions must have released.
Then in 2001, the group led by Prof McDonald announced that the neutrinos they were detecting in Ontario, which started out in the Sun, had also "flipped" from their expected identity.
This discovery of the particle's wobbly flavours had crucial implications. It explained why neutrino detections had not matched the predicted quantities - and it meant that the baffling particles must have a mass.
Image copyrightScience Photo LibraryImage captionThe Sudbury Neutrino Observatory, like Super-K, is housed in a cavern inside a mine
Prof Olga Botner, a member of the prize committee from Uppsala University, said although the work was done by huge teams of physicists, the prize went to two of the field's pioneers.
She said Prof McDonald had proposed and overseen the building of the Sudbury observatory in the 1980s, and been its director since 1990. "He has been the organisational and intellectual leader of this venture."
Found this article in the Kerala edition of The Hindu two days ago:
I know what you're thinking... Humans on Mars? Is it finally going to come true?
Well, maybe not untill 2030, according to an article by Space.com.
According to the site:
"The first human explorers on the journey to Mars are expected to be quite mobile, with the ability to explore long distances from their habitat, a region being called an "Exploration Zone." In current planning activities, NASA assumes an Exploration Zone radius of approximately 60 miles (100 km).
NASA plans to use existing assets at Mars, such as the Mars Reconnaissance Orbiter (MRO) and the Odyssey spacecraft, to support the selection process of potential Exploration Zones. However, the life expectancy of MRO and Odyssey are limited. NASA is eager to take advantage of the remaining operational years of those Martian imagers to gather high resolution maps of potential Exploration Zones while the spacecraft remain operational."
The spacecraft, according to the newspaper article, will be manufactured by 2017. So, basically, till then, the people who want to travel to Mars (like me) will have to wait for sometime for more news.
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