Hunt for ancient human molecules (Amazing Story!)

BBC ^ | Published: 2004/02/16 22:21:33 GMT | By Richard Black

[vannrox]

Hunt for ancient human molecules

By Richard Black

BBC science correspondent in Seattle

New technologies may soon allow scientists to identify some of the genes of humankind's oldest ancestors.

This raises the possibility of plotting the evolutionary tree of humanity from five million years ago to the present.

Professor Hendrik Poinar says DNA fragments should be recoverable from fossils that are a million years old, and proteins from even older times.

His comments came at the American Association for the Advancement of Science annual meeting in Seattle.

Professor Poinar, from McMaster University in Canada, said the key was to find fossils preserved so well that samples had not been degraded.

DNA, the biomolecule in cells that carries the "code of life", starts to fall apart rapidly under unfavourable conditions.

Proteins, on the other hand, which build and maintain the body and are constructed from information in the DNA, are more robust.

Beyond theory

The oldest protein from a fossil analysed so far was extracted from a bison (

Bison priscus

) which died 55,000 years ago.

The animal died in Siberia, where the intense cold acted like a natural deep freeze.

A team led by Christina Nielsen-Marsh, of Newcastle University, UK, extracted and identified samples of a bone protein called osteocalcin.

But Professor Poinar, who works out of McMaster's department of anthropology, believes we can go back substantially further.

"DNA, for example; in theory it should survive for about 100,000 years," he told BBC News Online.

"In reality, the oldest reproducible sequences go back around 300,000, so already we're beyond theory.

"But I think small fragments could survive for a million years, in a cold climate."

In 2001, a claim was made for the recovery of 1.8-million-year-old DNA found in a specimen taken from South Africa's Sterkfontein Caves, famous for their remains of ancient human-like creatures. But it was a claim that was greeted with wide scepticism.

However, the more durable proteins, Professor Poinar believes, could survive in samples as old as five million years.

That would take researchers back in time to beyond even "Lucy", the Ethiopian hominid that lived 3.2 million years ago and is thought to have given rise to the

Homo

line which ended in modern humans.

Location, location

From proteins, scientists can deduce genetic sequences which could be compared with equivalent genes in modern humans, enabling researchers to work out phylogenetic pathways and provide better information on what our ancient ancestors might really have looked like.

But where the sample is found and how it was preserved will be crucial.

"Realistically, permafrost and ice are the best places," Professor Poinar said. "If that is not possible, I would go for caves.

"You can go into caves and they can maintain constant conditions of temperature and humidity over long periods of time, even though the outside temperature may be way above what it is inside the cave."

After samples of a protein have been extracted, they must be analysed, using a relatively new technique known as time-of-flight mass spectrometry.

It is a slow but highly sensitive process that allows researchers to work out the protein's component parts. And from this information, scientists can reconstruct the genetic sequence that gave rise to the protein.

But Professor Poinar told the AAAS meeting that nothing could be accomplished without finding the right samples.

Relics of relatively modern human relatives such as Neanderthals have been found in caves. More samples of older hominids from similar sites would be most welcome, he said.

[vannrox]

cool.

[js1138]

ping

[ChicagoHebrew]

I say clone 'em. That would be the best way to learn about human evolution-- by studying a new, living "ancestor"

[Reelect President Dubya]

Professor Poinar, from McMaster University in Canada, said the key was to find fossils preserved so well that samples had not been degraded.

I see nothing new here.

This was the basic premise of Michael Crichton's "Jurassic Park."

[Joee]

Is this another attempt to shoot down creation, because if it is, it's just a waste of time. To date, not one attempt has succeeded in proving evolution. In fact, in todays world, the evolution theory is just as full of holes as it was when Darwin came up with it.

[DManA]

Think man! Since our ancestors probably helped them go extinct, the reparations we'd owe them would be astronomical.

I say clone 'em.

[gcruse]

More samples of older hominids from similar sites would be most welcome, he said.

Okay, but we'll have to beat the Army Corps of Engineers to the sites before they plow them under and pour concrete on top.  Don't want to offend the animist supersititions of whatever band of government-subsidized primitives may be setting foot there every five hundred years, thereby attaining native status.

[PatrickHenry]

PING. [This ping list is for the evolution side of evolution threads, and sometimes for other science topics. FReepmail me to be added or dropped.]

[LiteKeeper]

YEC INTREP

[alwaysconservative]

I vote we start with the DNA testing of Kennewick Man, just to assure ourselves of his ethnicity, hmmmmmm?

[gcruse]

You bet.

[Dimensio]

Is this another attempt to shoot down creation,

I'm not aware of any attempts to "shoot down creation" within science.

To date, not one attempt has succeeded in proving evolution.

Scientific theories are never proven.

In fact, in todays world, the evolution theory is just as full of holes as it was when Darwin came up with it.

Only because it never had any holes from the beginning.

[Victoria Delsoul]

Thanks for the interesting article, Patrick.

Bump.

[PeoplesRepublicOfWashington]

I say clone 'em. That would be the best way to learn about human evolution-- by studying a new, living "ancestor"

No need. We already have no shortage of Democrats running around.

[Ichneumon]

To date, not one attempt has succeeded in proving evolution.

Of course not -- science does not deal in "proofs". *No* scientific discovery or theory is proven. But they can still be used to build working fighter jets and computers.

In fact, in todays world, the evolution theory is just as full of holes as it was when Darwin came up with it.

Oh? Feel free to choose what you consider the very best example of a "hole" in the evolution theory and tell us what it is.

This should be fun.

[Dimensio]

Not only are they trying to demean and debase creation, they would like us to believe that the first humans appeared in Africa. LOL!!

I'm curious. What's your problem with the first humans appearing in Africa?

[<1/1,000,000th%]

It's all the 65 million year-old human fossils found by Dr. Dino. He'll be offering them on e-Bay soon as part of his bankruptcy filing. /sarcasm

[Joee]

A dog and a cat bred together making a Catsdography. ---- A real missing link somewhere? Was it the chicken or the egg? The lack of any fossile history out of millions of collected fossil's. Finally, and this will grab you, the Bible itself, which you believe or don't. Try Genesis as a starter!

[Dimensio]

A dog and a cat bred together making a Catsdography. -

Huh?

A real missing link somewhere?

What?

Was it the chicken or the egg?

I don't understand what you're trying to ask. The lack of any fossile history out of millions of collected fossil's.

What lack of "any fossile history"?

Finally, and this will grab you, the Bible itself, which you believe or don't.

You seem skilled at making statements that say absolutely nothing. "The Bible, either you believe it or you don't!". That has as much meaning as "Chocolate, either you like it or you don't.".

Try Genesis as a starter!

What does this have to do with the topic of discussion?