[Paleopsych] ABC: Ancient hair gives up its DNA secrets

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News in Science - Ancient hair gives up its DNA secrets - 22/06/2004 
http://www.abc.net.au/science/news/stories/s1135104.htm]
[This and several following are just articles that the one I just sent 
linked to. They should also be of interest, though I can't comment on them.]

     Anna Salleh
     ABC Science Online
     Tuesday, 22 June  2004

     Analysing DNA from ancient strands of hair is a new tool for learning
     about the past, molecular archaeologists say, including whether hair
     samples belonged to Sir Isaac Newton.
     Until now, scientists had thought analysing the hair shaft was of
     relatively little use as it contained so little DNA.
     Dr Tom Gilbert of the [4]University of Arizona led an international
     team that reported its work in the latest issue of the journal
     [5]Current Biology.
     The researchers said they had extracted and sequenced mitochondrial
     DNA from 12 hair samples, 60 to 64,800 years old, from ancient bison,
     horses and humans.
     The researchers said their results confirmed that hair samples
     previously thought to belong to Sir Isaac Newton were not his, a
     finding that backed previous isotopic analysis.
     But the focus of their research was to explore the potential of
     extracting ancient DNA from hair samples.
     The most common samples used for ancient DNA analyses are taken from
     bone, teeth and mummified tissue.
     Until now, when the hair root hadn't been available for analysis,
     scientists had thought analysing the hair shaft was of relatively
     little use as it contained so little DNA.
     But isolated strands of hair are often the only clues to human
     habitation in ancient times.
     Now Gilbert's team said it had developed a method to extract and
     sequence ancient DNA from hair shafts.
     The researchers said the ancient DNA in hair was much less degraded
     than DNA from other tissues.
     They argued this was because it was protected from water by the hair's
     hydrophobic keratin, the protein polymer that gives hair its
     structure.
     The team also found that hair DNA had a low level of contamination and
     argued that keratin may protect the DNA from contamination with modern
     DNA sequences, like DNA from human sweat.
     The scientists also said that analysing hair DNA, and potentially DNA
     from other keratin-containing samples like ancient feathers and
     scales, would minimise the destruction of valuable archaeological
     samples caused by sampling teeth or bones.
     Hairy development
     "It's a nice development," said Dr Tom Loy, an Australian expert in
     ancient DNA from the [6]University of Queensland.
     He said that molecular archaeologists had generally ignored extracting
     DNA from hair.
     "[But] on the basis of their article it looks as if it's quite, quite
     feasible," he told ABC Science Online.
     He said the method may be useful in shedding light on the origin of
     strands of ancient hair discovered a decade ago at the Pendejo Cave
     site in New Mexico.
     "It would be very important to find out whose hair it was," said Loy,
     who said previous attempts had been unsuccessful.
     He was enthusiastic about the idea of being able to extract ancient
     DNA from feathers.
     "Often times feathers are found in caves and in some cases as residues
     on artefacts," he said.
     But Loy was sceptical about using the method to extract ancient DNA
     from scales and was not convinced by the argument that keratin
     protected ancient DNA from contamination.
     "People still don't fully understand how things get contaminated," he
     said.

References

     4. http://www.arizona.edu/
     5. http://www.current-biology.com/
     6. http://www.uq.edu.au/