The insertion sequence IS6110 is frequently
used as a marker for the presence of ancient
DNA from bacteria of the Mycobacterium tuberculosis complex in
human archaeological remains. The specificity of polymerase chain reactions
directed at IS6110 has, however, been questioned, because identical or similar
elements have been identified in ‘mycobacteria other than tuberculosis’.
These are Mycobacterium
species, common in the environment, that may occasionally cause
opportunistic disease, but which are not normally associated with clinical
cases of tuberculosis.
In the first article
published in STAR: Science and
Technology of Archaeological Research, Muller et
al report the presence of two sequence types similar but not
identical to IS6110 in bone
samples from nine skeletons dated mainly to the Roman period, one from
Scotland and the others from the remainder of Britain. The source of these
sequences cannot be established but they most likely derived from environmental bacteria
that colonised the skeletons after death. Our data support the notion that
IS6110 may not be unique to the members of the Mycobacterium tuberculosis complex
and is therefore not suitable as a specific marker for the identification of
tuberculosis in human remains.
