There is some news about a report from Canada's CBC about fast-food chicken items containing as much as 50% soy protein, based on DNA testing. I won't do the report the service of linking to it directly, but you can search for the news "What's in your chicken sandwich? DNA test shows Subway sandwiches could contain just 50% chicken."
Isn't quantifying ratios of various DNA sequences fairly difficult, requiring rigorous sample preparation? Could results vary dramatically by varying cooking times, and the independent processing of the animal protein and the vegetable protein? Is there an reason to expect isolated DNA ratios to be a good indicator of protein ratios?
I'm also curious, is there a better way to at least try to do this study - perhaps search for key sequences of amino acids within the proteins to at least try to distinguish animal from vegetable proteins quantitatively?
edit: Here is a newer, more reliable, independent news item not written by the agency who paid for the testing.
The NPR news article DNA Tests Find Subway Chicken Only 50 Percent Meat, Canadian News Program Reports says:
The tests were conducted by a DNA researcher at Trent University's Wildlife Forensic DNA Laboratory, for a CBC Marketplace episode dedicated to testing fast-food chicken dishes, and have not been independently confirmed.
Later in the same article a strong statement by one of the companies refuting the results has also been provided.