Neanderthal Yields Nuclear DNA

The first sequences of nuclear DNA to be taken from a Neanderthal have been reported at a US science meeting. Geneticist Svante Paabo and his team say they isolated the long segments of genetic material from a 45,000-year-old Neanderthal fossil from Croatia.

The work should reveal how closely related the Neanderthal species was to modern humans, Homo sapiens.

Details were presented at a conference at New York's Cold Spring Harbor Laboratory and reported by News@Nature.

It is a significant advance on previous research that has extracted mitochondrial DNA (mtDNA) from Neanderthal (Homo neanderthalensis) specimens.

This genetic material is contained in structures that power cells; and although the information it holds is very useful, it is more limited in scope than the DNA bundled up at the cell's centre.

So far, Paabo and colleagues have managed to sequence around a million base-pairs, which comprises 0.03% of the Neanderthal's entire DNA "catalogue", or genome. Base-pairs are the simplest bonded chemical units which hold together the DNA double helix.

The genetic material comes from a 45,000-year-old male Neanderthal specimen found in Vindija Cave outside Zagreb, the News@Nature website reports.

* The double-stranded DNA molecule is held together by chemical components called bases
* Adenine (A) bonds with thymine (T); cytosine (C) bonds with guanine (G)
* These "letters" form the "code of life". There are estimated to be about 2.9 billion base-pairs in the human genome wound into 24 distinct bundles, or chromosomes
* Written in the DNA are 20-25,000 genes, which human cells use as starting templates to make proteins. These sophisticated molecules build and maintain our bodies
* Preliminary analysis shows the bundle of DNA responsible for maleness in the Neanderthal - its Y chromosome - is very different from modern human and chimpanzee Y chromosomes; more so than for the other chromosomes in the genome.

This might suggest that little interbreeding occurred between our own species and the Neanderthals.

Usually, DNA must be cloned in bacteria to produce large enough amounts to study. But Professor Paabo, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his team have used a novel sequencing method to decode the genetic material. This involves using tiny wells to directly sequence DNA fragments in an emulsion.

However, the researcher is also working to extract and read Neanderthal DNA by the traditional method. About 75,000 base-pairs have been sequenced this way so far. They show that Neanderthals diverged from the evolutionary line that led to modern humans about 315,000 years ago.

Neanderthals lived across Europe and parts of west and central Asia from approximately 230,000 to 29,000 years ago. It is unclear what factors led to their demise, but climate change and competition from modern humans may have played a role.

usual reprises, old links, probably expired, emphasis mine:

The Neandertal Enigma
by James Shreeve
Frayer's own reading of the record reveals a number of overlooked traits that clearly and specifically link the Neandertals to the Cro-Magnons. One such trait is the shape of the opening of the nerve canal in the lower jaw, a spot where dentists often give a pain-blocking injection. In many Neandertal, the upper portion of the opening is covered by a broad bony ridge, a curious feature also carried by a significant number of Cro-Magnons. But none of the alleged 'ancestors of us all' fossils from Africa have it, and it is extremely rare in modern people outside Europe." [pp 126-127]
Fathers can be influential too
by Eleanor Lawrence
Biologists have warned for some years that paternal mitochondria do penetrate the human egg and survive for several hours... Erika Hagelberg from the University of Cambridge, UK, and colleagues... were carrying out a study of mitochondrial DNAs from hundreds of people from Papua-New Guinea and the Melanesian islands in order to study the history of human migration into this region of the western Pacific... People from all three mitochondrial groups live on Nguna. And, in all three groups, Hagelberg's group found the same mutation, a mutation previously seen only in an individual from northern Europe, and nowhere else in Melanesia, or for that matter anywhere else in the world... Adam Eyre-Walker, Noel Smith and John Maynard Smith from the University of Sussex, Brighton, UK confirm this view with a mathematical analysis of the occurrence of the so-called 'homoplasies' that appear in human mitochondrial DNA... reanalysis of a selection of European and African mitochondrial DNA sequences by the Sussex researchers suggests that recombination is a far more likely cause of the homoplasies, as they find no evidence that these sites are particularly variable over all lineages.
Is Eve older than we thought?
by Sanjida O'Connell 15th April 1999
"Two studies prove that the estimation of both when and where humanity first arose could be seriously flawed... The ruler scientists have been using is based on genetic changes in mitochondria, simple bacteria that live inside us and control the energy requirements of our cells. Mitochondria are passed from mother to daughter and their genes mutate at a set rate which can be estimated - so many mutations per 1,000 years... However, these calculations are based upon a major assumption which, according to Prof John Maynard Smith, from Sussex University, is 'simply wrong'. The idea that underpins this dating technique is that mitochondria, like some kinds of bacteria, do not have sex... Two groups of researchers, Prof Maynard Smith and colleagues Adam Eyre-Walker and Noel Smith, also from Sussex, and Dr Erika Hagelberg and colleagues from the University of Otago, New Zealand, have found that mitochondria do indeed have sex - which means that genes from both males and females is mixed and the DNA in their offspring is very different... Prof Maynard Smith and his colleagues stumbled over mitochondria having sex in the process of tracking the spread of bacterial resistance to meningitis... For the 'out-of-Africa' theory to hold water, the first population would have to have been very small. Sexually rampant mitochondria may put paid to this idea. Maynard Smith thinks that the origin of humanity is much older - may be twice as old - which, according to Eyre-Walker, means we are likely to have evolved in many different areas of the world and did not descend from Eve in Africa."

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