From what I have read, it appears all the American Pettypools trace back to a William Pettypool who was the only son of William Pettypool in Essex, England during Medieval times. The immigrant William Pettypool arrived in the Virgina colonies in the 1650's. He also had a son named William.
Apparently, for unknown reasons, some of the children changed their surname to P'Pool in the early 1800's. (This is my line.)
Source: Pettypool One-Name sourcePettypool DNA Project
A fantastic site for Pettypool research is Colonial Pettypool-Poole-P'Pool Families
and recently I found:Descendants of William PettypoolNOTE: When listing a query or lineage info, please do so in the "Discussion Forum" section below as only the post in that section will be picked up by the RSS reader and distributed to those of us who have chosen to use it. Thanks!