American breeding Right Handed Negative

There is possibly something in it. More deep research needs to go into it. There are too many variations in Pedigrees to say A is USA and B isn't, the USA is just where the horse was born.
Street Cry is IRE but he was never trained there or ran there.
Sadlers Wells is USA but he was never trained or ran there (to my knowledge)
If you know of any Sire lines that are all USA born bred and raced and researched them then it may produce some surprising results. But I think the gene pools are so mixed up with IRE, USA etc so I think it will be a difficult one to profit from unless you really know your USA pedigrees.