DNA is becoming the standard in most breeds, DNA profiling in the Neapolitan Mastiff is slowly catching on.  Recently the AKC mandated that all imported dogs into the United States be DNA profiled prior to registering offspring.  The AKC DNA database examines the parentage of AKC DNA profiled registered dogs and litters whelped after January 2000, as the Neapolitan Mastiff DNA database grows the authenticity of pedigrees will increase.

"AKC DNA Profiles are generated using the same technology used by law enforcement agencies throughout the world. How does this work? In humans and dogs alike, each gene is present as two copies (displayed as letters). Offspring receive one copy of each gene from each parent in a random process.  This technology does not use actual genes, but other DNA sequences that are also inherited one copy from each parent." (From the AKC DNA Site)

You can order a pre-paid DNA kit for $35 or a free kit with a $40 process fee from the AKC - it requires taking a simple cheek swab from your Neapolitan.