To be clear I am not a DNA expert, I am not a statistician, I am not a forensic scientist. I have done PCR. I have modelled using Bayesian statistics. I do know what 'a priori probabilities' are, and I did not say you wrong in the use of the term nor that the term was wrong, I just said no one who actually used Bayesian statistics would talk about 'Bayesian a priori probabilities'. You are simply wrong about game theory being just statistics, it is an entirely separate field of mathematics.
See
http://mathworld.wolfram.com
game theory is a subset of applied mathematics, it is not a subset of probability theory / statistics. Game theory predominantly involves deterministic games, the opposite of probability theory.
Guede's DNA is essentially only corroborating evidence. Had there been no DNA Guede would likely have been convicted.
1) Guede admits to his presence at the time and place of the murder and that he was the last person to see Kercher alive. He also states he entered Romanelli's room
2) His statement is corroborated by details (the toilet use, the towel use) that he would only have known if he was present. (Compare Knox's statement, where the only corroboratable fact; who else was present was proven in error).
3) Guede's bloody handprint places him at the time and place of the murder.
4) Shoeprints in fresh blood matched shoes that Guede was known to have possessed (empty shoe box) but which he disposed of.
5) The DNA for Guede was qualitatively different from Sollecito's. a) The DNA samples were collected by different teams at different times, the Perugian police at the time of the initial investigation, the forensic pathologist from the victim's body, and some 6 weeks later from clothing collected by the team from Rome. Although all samples were analysed in the same laboratory. b) There were multiple positive samples. c) The positive results were from different laboratory runs. d) Guede was not known to have had a legitimate presence in the flat, whilst Sollecito was there before and after.