Hello there,
I agree with sunmoonstars that the amount of DNA present in the fruits will likely have no correlation with how healthy the fruits are for us. There are definitely other parameters you can look at though, such as sugar content, vitamin c content, etc. (
http://healthyeating.sfgate.com/fruits- ... -4703.html) that may give you a better idea of what makes a fruit "healthy". You should definitely do some online research to see what studies have been done to determine what makes a fruit "healthy", and what kind of aspects have been looked at, and from those, try to formulate some new ideas/questions you would like to test.
Please post back if you have anymore questions!
Connie