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.

[Dimensio]

I have no problem with something that never was; but I do have a problem with lying.

What, exactly, makes you think that it is a lie?

[Doctor Stochastic]

Perhaps you will show us which papers are knowingly mistating the evidence? Show your own evidence (or references thereunto) as to why the researchers are knowingly wrong.

Or are you just flinging the term "lie" at some unnamed people about some unreferenced work? Strong words with no supporting evidence brings into question your bona fides.

[adam_az]

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

Would you care to enumerate the holes for us?

What do you think the evidence points towards and why?

[adam_az]

Patrickhenry, could you please add thegreatprion to this list?

thegreatprion, this is the article I told you about.

[Old Professer]

Cold.

[Alamo-Girl]

I don't know the url, but I join in praying for this young man!

[Alamo-Girl]

Oops. Right message, wrong window. Sorry about that! Thanks for the ping, PatrickHenry!

[PatrickHenry]

I've done that too.

[Modernman]

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

Duh. Because, that's where black people come from. There are some people who are very uncomfortable with the fact that everyone on Earth shares a common ancestry.

[Modernman]

A dog and a cat bred together making a Catsdography

What?

A real missing link somewhere?

What is this supposed missing link supposed to link?

Finally, and this will grab you, the Bible itself, which you believe or don't. Try Genesis as a starter!

What about the hundreds of other creation myths that humanity has come up with over the centuries? What makes you so sure that the Hindu creation story isn't more accurate than the one you believe in? Other than faith, do you have any evidence that supports your particular creation myth?

[Joee]

Apparently you hold the belief that you are a product of something crawling out of the ancient slime, and evolving into a fine young person, of considerable intellect. So be it!

As for me, I prefer to believe I am the product of divine planning, put on this orb to meet certain criteria and destined to do further work for the Lord in eternity.

I have done some reading on Creation vs Evolution and can find no evidence to support Evolution when it comes down to the nitty gritty. I offer the following URL for your possible interest.

Again, thank you for your thoughtful response.

http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=37148

[Dimensio]

Apparently you hold the belief that you are a product of something crawling out of the ancient slime, and evolving into a fine young person, of considerable intellect. So be it!

Perhaps if you would actually argue what your opponent believes rather than making up their position for them you would have more credibility. Then again, it would greatly weaken your arguments.

Your WorldNetDaily citation is confusing. The article is about the percentage of people who believe in a literal interpretation of Biblical stories, but I don't see what that has to do with the issue of evolution.

[PatrickHenry]

As for me, I prefer to believe I am the product of divine planning, put on this orb to meet certain criteria and destined to do further work for the Lord in eternity.

What work could you possibly do for a deity capable of creating the whole universe and every living thing within it?

[whattajoke]

touche.

This thread has thus far certainly brought about some intetesting new takes on these issues.

[Doctor Stochastic]

...I prefer to believe ...

Another example of the identity of Creationism and PostModernDeconstructionism. Prefences rather than evidence.

[whattajoke]

they would like us to believe that the first humans appeared in Africa. LOL!!

Welcome to FR. While I would usually chalk up your off-the-wall statement to just another troll, in combination with your screen name, my eyebrows were raised.

While it appears that you are insulted or afraid of the obvious facts that humans did indeed spring from Africa, I'm curious as to what you actually think on this matter.

Your week's worth of posts on things such as "FREE MILOSEVIC," "Monkey is not a racist term," "Mexicans are NOT Europeans and get the hell out of my country" aside, please do help us ignorant folks as to where the cradle of civilization was, exactly.

[Cogadh na Sith]

Yeah, except that wasn't real and this is...

[Joee]

That's exactly what I have been saying. There is no valid evidence of Evolution.

[Joee]

Evolution leaves you with that major problem to explain. Which was 1st the chickens or the eggs?