A team of researchers has obtained a dinosaur bone (Tyrannosaurus rex) and has attempted to extract ancient DNA from it. Using primers to the 12S rRNA mitochondrial gene, they have used PCR and obtained a DNA segment that yields a sequence homologous to crocodile DNA. Other scientists are skeptical that this sequence is really from the dinosaur. Instead, they believe that it may be due to contamination from more recent DNA, such as the remains of a reptile that lived much more recently. What criteria might you use to establish the credibility of the dinosaur sequence?