Scientists have for the first time grown a complex, fully functional organ from scratch in a living animal by transplanting cells that were originally created in a laboratory.
British scientists produced a working thymus, a vital immune system "nerve centre" located near the heart.
In future the technique, so far only tested on mice, could be used to provide replacement organs for people with weakened immune systems, scientists believe.
But it might be another 10 years before such a treatment is shown to be effective and safe enough for human patients.
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Rain will affect most of the UK today, with Scotland remaining largely fine and brighter spells appearing in the east and south.
In a searingly emotive address, the president cast Hillary Clinton as the most qualified candidate to unify America as next US president.
The release is the second batch in a series of leaks that have rattled the Democratic Party.