Hi, What your looking for is called a "landrace" strain. That is -- one of pure Indica, or Sativa that is unaltered, absent with any foreign genes, and that is specific to that region.
I have a fascination with these strains... hey.. what PURE 100% INDICA OR SATIVA, dosen't appeal to a pothead? Hehe. You will never ever ever find a pure 100% unbred/crossed cannabis strain on the streets, only way to smoke it, is to grow it, or maybe a foreign visit
Since Africa is close to the equator and receives much sunlight and long growing seasons, Sativa is the landrace strain of African countries... Haze's.
In afghanistan, higherup's in the kush mountains, Indica's are the landraces of that reigon, due to cold mountainious climate and short growing seasons. Interestingly enough, since the mountains are at such an elevation -- it receives more UVB light, which produces more THC and resin.
A seed breeder called "World of Seeds Landrace", sells mannnny strains of landrace, colombian, thai, afghanistan, africa, brazil, ketema... so I think that's who your looking for. Check them out at Dr Chronic here
http://www.drchronic.com/products.asp?category=World+of+Seeds+Landrace
Im actually growing a PURE LANDRACE KUSH 100% Indica this summer, from DNA genetics, from the Mazar Sharif reigion in Afghanistan. You can check that out here:
http://www.cannabis-seeds-bank.co.uk/dna-genetics-pure-afghan-2610-p.asp
I noticed something interesting.... Think of the DANKEST strains you've ever seen, heard of, or smoked. Now look at their lineage of genetics. I noticed... if its Indica dominant, that 50-80% of the time... the strain lineage is ( HYBRID STRAIN ) x Pure Afghan Indica ( Kush ). So there's just something about them darn mountains and paki's that produce a fineeeee ganja
Hope that helps!
P.S. I would assume this isn't true.. with quality genetic company's like DNA/WOS... but in nature, I think most wild cannabis is hermaphrodite... how else would it self propagate itself.. with the absence of males?