Originally Posted by
Token
Do a test: delete a random 200.000 SNPs from your raw data and upload it to DNAland, you will see how much your ancestry report will change. With less markers tested, more imputation of the 'gaps' in your genome is needed, and less accurate will be your results. I wonder from where you got this 30% from, almost all markers are relevant for an accurate report.
If he is not interested on deep ancestry, then i don't see the motive for a genetic test. They will tell him what he already knows, that he is 100% Portuguese (considering that he have no foreign ancestry in the last 3-4 generations, which is always a possibility).