Estimating the integrity of aged DNA samples by CE

A CE/UV method was developed to separate by a micellar system the four DNA bases
and other five purinic–pyrimidinic compounds (5-methyl-cytosine, uracil, xanthyne,
hypoxanthyne and 5-bromo-uracil). Selectivity, precision, accuracy and sensitivity were
assessed and proved to be suitable for the analysis of the primary structure of DNA. This
method was adopted to study 16 aged samples including two Egyptian mummies,
formaldehyde-fixed paraffin-embedded tissues and other forensic specimens. Lower
relative values of the four canonical unmodified DNA bases (uDNAb) and more complex
pherograms were found in the aged samples when compared with the modern controls.
The results of the CE analysis, together with those obtained by classical molecular
methods (agarose gel electrophoresis, DNase I and RNase A assays, and UV spectrophotometry),
were finally evaluated for assessing the reliability of STR typing. Since
samples with low uDNAb showed no amplification or unreliable STR profiles, the
uDNAb value is discussed as a further quality criterion in the evaluation of the genetic
data obtained from aged samples.