entitled: ''Revisiting ancient mtDNA equid sequences from Pompeii''.
The author reports our mtDNA studies [Di Bernardo et al., 2004a,b] on six equine mtDNA sequences labeled CAV1-5 and CAVH, respectively, recovered from the ancient Roman towns of Pompeii and Herculaneum, buried by the Vesuvius eruption in AD79. We stated that ''our findings provide evidence that the remains analyzed are those of horses and mules and do not include either donkeys or hinnies'' [Di Bernardo et al., 2004a] and that ''the peculiar sequence polymorphisms shown by CAV5 could suggest to belong to a haplotype, which has either not yet been documented in GenBank or has since disappeared.'' Dr. Gurney suggests that in CAV5 analysis ''we have inadvertently hybridized a horse mtDNA sequence with an ass mtDNA sequence'' just because the first 177 nucleotides match closely with ass sequences in Genbank while the second section of 193 nucleotide matches closely with horse sequences in Genbank. She also says ''these two sections correspond exactly to the two different PCR: primer pairs that the authors used.'' First of all, I would like to point out that our experimental procedures in carrying out PCR on ancient DNA strictly obey to well established guidelines to avoid contamination [Cooper and Poinar, 2000; Hofreiter et al., 2001].
In particular, as reported in the Material and Method sections of our papers, at least two DNA extractions, carried out by different operators, and using different parts of the intact long bone, were taken for each bone sample. Moreover, each DNA sample was subjected to independent PCR amplification. DNA extraction and pre-PCR and post-PCR steps were carried out in physically separated laboratories, all surfaces and instruments were bleached, and plastic ware and solutions underwent UV irradiation. The operators wore fresh body protection for each pre-PCR step, and wore gloves and face masks throughout the entire pre-PCR and PCR work. Each PCR included two negative controls, i.e., a PCR control and an extraction control. The bone was first cleaned with a brush to remove the outer layers and surface contamination.