Ancient horse bone yields oldest DNA sequence

The study massively extends the time period for which DNA can be used to reveal ancient biological secrets

A fragment of a fossilised bone thought to be more than 700,000 years old has yielded the genome of an ancient relative of modern-day horses.

This predates all previous ancient DNA sequences by more than 500,000 years.
The study in the journal Nature was made possible because the bone was found preserved in Canadian permafrost following the animal's demise.
The study also suggested that the ancestor of all equines existed around four million years ago.
A remnant of the long bone of an ancient horse was recovered from the Thistle Creek site, located in the west-central Yukon Territory of Canada.
Palaeontologists estimated that the horse had last roamed the region sometime between a half to three-quarters of a million years ago.
An initial analysis of the bone showed that despite previous periods of thawing during inter-glacial warm periods, it still harboured biological materials - connective tissue and blood-clotting proteins - that are normally absent from this type of ancient material.
DNA puzzle

Nelson Mandela's condition deteriorates

The condition of former South African leader Nelson Mandela has deteriorated in the last few days, presidential spokesman Mac Maharaj has said.

The announcement came as President Jacob Zuma cancelled a trip to Mozambique following consultations with Mr Mandela's doctors.
Mr Mandela, 94, South Africa's first black president, has been in hospital since 8 June with a lung infection.
Emotional crowds continue to gather outside the Pretoria hospital.
They have been adding messages of support for Mr Mandela, known by his clan name Madiba.
Correspondents say South Africans now seem resigned to the prospect of his death.
"We don't like seeing Mandela going through so much pain, he has had a tough time in his life and he's gone through a lot of struggle. I think this struggle should get over sooner," Khulile Mlondleni told the BBC.
"We are all going to feel bad when he passes [away], but at the same time we will be celebrating his life. He has done so many great things for this country," said 25-year-old John Ndlovu, quoted by Reuters news agency.

Obama begins Africa tour in Senegal

 

US President Barack Obama has arrived in Senegal on the first leg of a three-nation tour of Africa.

It is Mr Obama's second visit to the continent since he became president.
He is hoping to boost economic ties with the African countries and promote good governance - all the countries he is visiting have stable democracies.
The South African leg of his trip is expected to be overshadowed by the continuing critical condition of former President Nelson Mandela.
The White House has said it will defer to the wishes of Mr Mandela's family over whether Mr Mandela is well enough to receive a visit from him in hospital.
Mr Obama, who arrived in the Senegalese capital, Dakar, on Wednesday night with his family, is due to meet the country's President Macky Sall later on Thursday.