Thursday, August 2, 2012
Saturday, January 2, 2010
'Lifeless' prion proteins are 'capable of evolution'
Scientists have shown for the first time that "lifeless" prion proteins, devoid of all genetic material, can evolve just like higher forms of life.The Scripps Research Institute in the US says the prions can change to suit their environment and go on to develop drug resistance.
Prions are associated with 20 different brain diseases in humans and animals.
The scientists say their work suggests new approaches might be necessary to develop therapies for these diseases.
In the study, published in the journal Science, the scientists transferred prion populations from brain cells to other cells in culture and observed the prions that adapted to the new cellular environment out-competed their brain-adapted counterparts.
When returned to the brain cells, the brain-adapted prions again took over the population.
Charles Weissmann, head of Scripps Florida's department of infectology who led the study, said: "On the face of it, you have exactly the same process of mutation and adaptive change in prions as you see in viruses.
Wednesday, December 9, 2009
Thursday, September 10, 2009
Ancient skeletons discovered in Georgia threaten to overturn the theory of human evolution
By David Derbyshire
For generations, scientists have believed Africa was the cradle of mankind.
Now a stunning archaeological discovery suggests our primitive ancestors left Africa to explore the world around 800,000 years earlier than was previously thought before returning to their home continent.
It was there - hundreds of thousands of years later - that they evolved into modern humans and embarked on a second mass migration, researchers say.
The Georgian bones - which include incredibly well preserved skulls and teeth - are the earliest humans ever found outside Africa. The remains belong to a race of short early humans with small primitive brains who walked and ran like modern people. They were found alongside stone tools, animal remains and plants - suggesting that they hunted and butchered meat. Archaeologists now believe that our ancestors left for Europe at least 1.8million years ago, before returning to Africa and developing into Homo Sapiens
Prof David Lordkipanidze, the direct of the Georgian National Museum, said: 'Before our findings, the prevailing view was that humans came out of Africa almost 1million years ago, that they already had sophisticated stone tools, and that their body anatomy was quite advanced in terms of brain capacity and limb proportions. But what we are finding is quite different' He said Africa was still the unchallenged cradle of mankind. But he added: 'Georgia may have been the cradle of the first Europeans.'
