Louis-Antoine de Bougainville was the first Frenchman to circumnavigate the globe. In 1768 he landed in the Solomon Islands, The island where they lived for a time is now named Bougainville Island.
DNA indicates some decent from Bougainville Island. I'm trying to locate the crew manifests from his voyage. The logical assumption is a crewmen "married" a local native woman and they bore children, hence their DNA showing up in ours.
I really need to narrow the possible candidates, we had many seamen in the family.