For more detailed information, please visit: P-rr-tt DNA Project.
There are several different Parrott lineages in the US & elsewhere, which were declared to be 'Kinsmen all' some 60 years ago by the first comprehensive book on Parrott genealogy, Links that Bind.
Thanks to DNA, it is now obvious the P-rr-tts are not all related to each other, and there are at least 50 different families in the US alone. We are just now figuring out which are/are not related to each other within North America. However, at this point, we can only speculate on which European Parrott lineages they might be related to for all but very few of the North American families.
Most of the test participants so far have come from the US. More participants are need from the UK, Ireland, Australia and New Zealand in order to round out the results.
As far as the American families go, most information is available on the Southern families. Almost none of the New England families have participated in the DNA testing, so the least is known about them.