And the court-appointed independent investigators for her appeal thoroughly refuted both the findings of the evidence itself and competency of the methods used to collect it. None of that is credible any more. Or, at least, none of it should be.
From the Perugia Murder File website:
Dr. Stefanoni's investigation and forensic findings were independently reviewed by Dr. Renato Biondo, the head of the DNA Unit of the scientific police, in 2008. He provided confirmation that all the forensic findings were accurate and reliable and he praised the work of Dr. Stefanoni and her team.
The Kerchers hired their own DNA expert, Professor Francesca Torricelli, who also confirmed that Meredith's DNA was on the blade of the double DNA knife.
Raffaele Sollecito knew that Meredith's DNA was on the blade of the knife, which is why he claimed on two separate occasions that he he had accidentally pricked Meredith's hand whilst cooking.
From the same thread:
It also should be noted that it isn't 'required' that there be a high enough amount for an independent retest in Italian courts, since as standard under Italian law, Amanda and Raffaele's legal teams were invited to be present when the tests were performed so they could observe that they were performed correctly and the results were accurate. They declined the invitation. This is one of the reasons their complaints on the knife DNA were rejected by Judge Massei
ETA: I don't know if Knox is guilty or innocent. I'm in neither camp on this one. Just for reference.