|
|
Dolly is the first mammal to have been successfully cloned from an adult
cell
1997: Dolly the sheep cloned by scientists
England have
Scientists in Scotland have announced the birth of the world's first
successfully cloned mammal, Dolly the sheep.
Dolly, who was created at the Roslin Institute in Edinburgh, was actually
born on 5 July 1996 although her arrival has only just been revealed.
Dolly is the first mammal to have been successfully cloned from an adult
cell. Previous clonings have been from embryo cells.
The sheep's birth has been heralded as one of the most significant
scientific breakthroughs of the decade although it is likely to spark ethical
controversy.
Scientists in Scotland cloned a ewe by inserting DNA from a single sheep
cell into an egg and implanted it in a surrogate mother.
They now have a healthy seven-month-old sheep - Dolly - who is an exact
genetic duplicate of the animal from which the single cell was taken.
DNA tests have revealed that Dolly is identical to the ewe who donated the
udder cell and is unrelated to the surrogate mother.
Embryologist Dr Ian Wilmut, from the Roslin Institute, said: "It will
enable us to study genetic diseases for which there is presently no cure and
track down the mechanisms that are involved."
The research, published in Nature magazine, follows the Edinburgh team's
success in cloning sheep embryos. Last year they produced two identical sheep,
which were clones of an original embryo.
The company which has bought the rights to the research, PPL Therapeutics,
said Dolly would help to improve understanding of ageing and genetics and lead
to the production of cheaper medicines.
US President Bill Clinton has set up a special task force to investigate
cloning in order to examine the legal and ethical implications.
President Marcos claims to have control of the army
1986: Filipino coup leaders tell Marcos to go
Artificially 1969:
The Two senior members of the Philippines government have taken refuge in
the defence ministry building in the capital, Manila, after denouncing President
Ferdinand Marcos.
Yesterday, Defence Minister Juan Ponce Enrile and chief of staff
Lieutenant-General Fidel Ramos accused the president of planning to arrest
leaders of the opposition.
They called on ministers and army officers to help them topple Marcos and
then took over Camp Aguinaldo, the defence ministry.
Speaking from Camp Aguinaldo, Mr Enrile told the press Mrs Aquino had won
the election and Marcos should step down.
"We had no plans to stage a coup d'etat. But we are going to defend
ourselves from an imminent assault," Mr Enrile said.
Lt-Gen Ramos told American TV all 13 regional army commanders had pledged
their support for a coup, while Marcos claimed he had control of "99% of the
military".
Heavily armed troops have surrounded the building and President Marcos has
said the situation is "under control".
He also accused the two men of conspiring to assassinate him and his wife,
Imelda, and demanded their surrender.
In elections held on 7 February, the main opposition party, led by Corazon
Aquino, and President Marcos both claimed victory.
The US has attempted to mediate by sending US special envoy Philip Habib
who reports back to President Reagan later today.
Mrs Aquino, widow of Benigno Aquino assassinated on his return from exile
three years ago by Marcos supporters, rejected Mr Habib's proposal last week for
a power-sharing government.
Mrs Aquino has accused the president of stealing power and called for a
one-day general strike next week and a boycott of businesses owned by the Marcos
entourage .
The head of the Roman Catholic Church in the Philippines, Cardinal Jaime
Sin, is also demanding an uprising.
He has called on the people to support Mr Enrile - despite the fact that he
helped Marcos impose martial law in 1972 - and Lt-Gen Ramos.
"If such a government does not of itself freely correct the evil it has
inflicted on the people then it is our serious moral obligation as a people to
make it do so," he said.
"The way indicated to us now is the way of non-violent struggle for
justice."
Vocabulary:
surrogate: a deputy; a delegate; a substitute(代孕的)
entourage: surroundings; specif., collectively, one's attendants or
associates(随从;周围) |
|
发表于 2016-7-9 23:23:06