[Archport] Discussão sobre preservação de material osteológico

["Francisca Alves-Cardoso" <francealves@netc.pt>]

Car@s Colegas

 

Julgo que esta discussão é de interesse para os profissionais que trabalham com material osteológico (humano e não só).

 

Cumprimentos,

Francisca Alves Cardoso.

---------- Forwarded message ----------
From: White, Bill <BWhite@museumoflondon.org.uk>
Date: 2008/6/12
Subject: Re: [BABAO-L] The Washing of Bones
To: BABAO-L@jiscmail.ac.uk

Alan,

 

Undoubtedly the survival of aDNA is theoretically at risk in the presence of water, as there are a large number of chemical bonds in the DNA molecule that are subject to hydrolysis. However, this is not to say that the requisite chemical cleavage of the bonds in DNA will occur passively in water at neutral pH. Burials in London are usually in the London Clay but occasionally in Brick Earth. Bones may often be freed of the latter by gentle brushing but many thousands of human skeletons excavated in London have required washing in water to free them of adherent clay. We have no evidence that this has been inimical to the intrinsic DNA. Few studies on the DNA of individuals have been performed on material in the Museum of London research collection but analysis for pathogen DNA (usually Mycobacterium tuberculosis complex) has often been positive. In 1999 the skeleton of the Spitalfields Roman lady was found lying in a "sludge" in an unsealed lead coffin. Despite exposure to rain and groundwaters for 1,600 years her DNA was recovered, amplified and analysed.

 

Our experience does not suggest the necessity for abandonment of washing human bones in water, which in any case is the only realistic measure for large samples. However, Andrew Millard has cautioned against washing bones in hot water, wherein extant lipids might then be lost. Nevertheless, aDNA in bones is at much greater risk of degradation if the bones have been subjected to  _running water_ for a protracted period, e.g. recovery from a riverine environment.

 

Bill

Bill White
Curator,Centre for Human Bioarchaeology
Museum of London
150 London Wall
London. EC2Y 5HN
Tel: +44 (0) 20 7814 5649
Fax: 0870 444 3853
Email: bwhite@museumoflondon.org.uk
www.museumoflondon.org.uk

---

From: BABAO E-mail discussion list [mailto:BABAO-L@JISCMAIL.AC.UK] On Behalf Of Alan Gillott
Sent: 11 June 2008 23:01
To: BABAO-L@JISCMAIL.AC.UK
Subject: [BABAO-L] The Washing of Bones

Having recently observed a particularly worrisome example of human bone washing (I will not name and shame) I thought it might be worth canvassing some opinions on the subject: what follows is an extract of some key points on the subject. The paragraphs below are extracted from a paper of mine which is not in the public domain.

 Alan

 …Archaeological Science at PPG16 interventions (EH 2006) – these documents, which at best are opinion, are liable to be followed by many as the way to do things. The latter document which is subtitled 'Best Practice guidance for Curators and Commissioning Archaeologists' contains in clause §5.2.6 under the general heading 'general specification for Archaeological Excavations' the following statement:

 'Burials should be recorded in situ and subsequently lifted, washed in water (without additives), marked and packed…'

 The bold is my emphasis. Washing bones in water is a controversial practice and two experts. Matthew Collins (pers. comm.) of York University and Frederika Kaestle of Bloomington University (pers. comm.) both confirmed that water damages aDNA and the practice of washing bones as a routine process contaminates aDNA by washing contaminating DNA deep into the bone Matrix. (Kaestle and Horsburgh 2002, 111). In the Molecule Hunt James Martin (2001, 28-29) describes how in amino acid racemization, Hendrik Poinar 'found a test to assess dryness of an ancient biomolecule. It was not just a measure of how dry specimens were now but constituted a kind of cumulative record of any tiny quantities of water that might have reached the biomolecules in the past.' (Jones M, 2001 28-29). Jones also states:

"The major enemy of ancient molecules is undoubtedly water. Chemists describe it as the 'ultimate catalyst', the trigger whose presence is needed for so many chemical reactions we encounter…We have seen how the very dry sites have conserved a rich array of biomolecules, and the same is true on a microscopic scale…." (Martin, 2001 238)

It is also possible to imagine that washing removes traces of adjacent soils that a soils expert might someday use to examine the conditions adjacent to a body; damages delicate trabecular bone, and, in the absence of any admonition to use distilled water, tap water includes contaminants added, or not removed, in the purification process.

 Bibliography

 English Heritage (2006) 'Archaeological Science at PPG 16 Interventions: Best practice Guidance for Curators and Commissioning archaeologists', http://www.english-heritage.org.uk/upload/pdf/archaeological_science_at_ppg16.pdf. Page consulted Monday, October 30, 2006.

 Kaestle, F A and Horsburgh, K A (2002) 'Ancient DNA in Anthropology: Methods, Applications and Ethics', Yearbook of Physical Anthropology 45, 92-130

 Jones, M (2001) 'The Molecule Hunt: Archaeology and the Search for Ancient DNA'. New York: Arcade Publishing.

 

-- 
Francisca Alves Cardoso, PhD.

Department of Archaeology, 
Durham University
UK