No need to read up i understand the basics, an nothing is pure as you think, nowt bar the wolf or fox or whatever is the true wild ancestors of our mutts.
A mate of mine had his whippet a dna test and it come back with dalmation, sheltie collie an staffy in it haha he then took his full saluki an it come back with greyhound an hound blood in it haha
Your mates certainy wasnt a saluki then go check your talking shite
It fcuking is, imported dog from germany or summat, more paperwork than sense. Like ivvsaid going by your definition then everybreed bar the wolf and its first crosses are mongre