@Basenji_Boy:
Due to a limited gene pool, they went to Africa and brought back more dogs.
http://basenji.org/african/intro.htm
This site will help, be sure to check the online library.
The 'domestic' lines of Basenjis come down from about 12 original dogs imported to the western world in the 1930s.
There were the imports BBoy mentioned added in the late 1980s. Then there were more imports brought in over the last few years, who will also hopefully be added to the AKC registry in the next year or so.
Most of the latter day imports, and their decendants (when bred to other Avongara dogs) go by the registered name "Avongara" ..which indicates they are 100% blood from recent imports. Some breeders focus on breeding lines of Avongara dogs to keep long lines of separate genetic material. Some breeders mix Avongara lines with their domestic to infuse new genes. Some breeders have only domestic lines.
All Basenjis with the brindle pattern go back to the Avongara dogs somewhere in their pedigree. That is a color that was reintroduced with the 80s imports.
Hopefully that helps a little