Mycobacteria have a tough cell wall, characterized by a very
high lipid content, including mycolic acids. This cell wall is
believed to be responsible for the persistence and survival of
tubercle bacilli throughout the lifetime of a mammalian host,
and during the initial decay process. It is therefore not surprising
that the first example of the detection of ancient
microbial DNA was that of Myco. tuberculosis (Spigelman and
Lemma 1993). With the exception of the special preservation
conditions associated with a bog body (Fricker etal. 1997) or
mummies (Salo etal. 1994), successful studies of ancient
microbial DNA have all been based on bone samples (Rafi
etal. 1994; Baron etal. 1996; Taylor etal. 1996). Bone is an
excellent material for the preservation of microbial DNA,
possibly because it provides stearic protection and limits
access by compounds required for microbial metabolism
(Eglinton and Logan 1991).
The aim of the current study was to determine whether
ancient microbial DNA could be detected by the polymerase
chain reaction (PCR) in another type of sample. During the
excavation of a Byzantine basilica in the Negev desert at
Karkur, conducted under the auspices of Dr P. Figueras from
the University of Be’er Sheva, Israel, a fragment of what
appeared to be calcified tissue, possibly lung pleura, was
found in the chest cavity of the body of a male aged 35–