zeb: I saw a doco sorry cant recall the details of graves found in Spain which were Neanderthal. This was proven by artefacts' etc. The finders took some samples and tested for DNA and found guess what? Not human.
Hi zeb, I guess I shouldn't comment without reading the article you referred to, but I'll hazard some guesswork.
I think your reference may have been to a claimed discovery of DNA from soil samples, which was an interesting claim as ancient DNA is usually found in small quantities that are often fragmentary and damaged, as this extract from a Smithsonian Institute discusses:
Quote: "Organisms decompose after death. Water, oxygen and microbes break down DNA. Within 100,000 years, all DNA is destroyed. Ancient DNA tends to be found in small quantities. The DNA that is extracted is generally fragmentary and damaged. Some damage results in changes to the DNA sequence. Cytosine can change to uracil, which is read by copying enzymes as thymine, resulting in a C to T transition. Changes from G to A also occur. DNA errors are very common at the ends of molecules."
That's not to say the skilled technicians can't come up with a result by making allowances for 'known' potential changes. But before I (personally) would include that information in my thinking, I will wait for further research.
The above Smithsonian article also stated that Neanderthal and humans share some DNA (but not all) sequences.
Quote: "Researchers have developed ways to analyze the results of ancient DNA sequencing efforts to determine whether contamination is likely and how much has occurred. Analysis of the results and efforts to keep labs and specimens free of modern DNA is very important as some researchers believe that the early studies of Neanderthal DNA included modern contaminants."
Here's the link to the above article:
http://humanorigins.si.edu/evidence/genetics/ancient-dna-and-neanderthals/sequencing-neanderthal-dna
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Earnest: It is also quite significant that these fossils were found in Morocco. Previously it had been thought that early man developed in East and Southern Africa. The identification of such old fossils so closely related to modern man in an area far from the "cradle of mankind" suggests palaeontologists simply have no idea where homo sapiens came from. Clearly they will have to revise their current assumptions.
Not sure Earnest, what point you're inferring, outside of your final sentence, quote:
"Clearly they will have to revise their current assumptions."
But that's what happens all the time in the 'scientific method.' And most of the media references to the discovery mention the change to previous thinking, in their conclusions.
I suggest that at this stage, there is no need to postulate a change to the 'supposed' beginnings/origins of humans. If the Moroccan discovery conclusions are sustainable in the long run, then all it means is that the spread of proto-humans (if that's the best descriptive term) occurred earlier than previously thought, and in a different direction to what was previously thought. And, I'm sure you will agree that humans could walk a long, long way in a few thousand years.
The discovery doesn't really change (to any great extent) current thinking about human origins. If as this 2002 discussion in the New York Times states, human origins may be far older than 300,000 years BP.
Quote: "The first human ancestors appeared between five million and seven million years ago, probably when some apelike creatures in Africa began to walk habitually on two legs. They were flaking crude stone tools by 2.5 million years ago. Then some of them spread from Africa into Asia and Europe after two million years ago."
Reference: www.nytimes.com/2002/02/26/science/when-humans-became-human.html