The kipunji. Photo from National Geographic by Tim Davenport.
Using fecal sample from Udzungwas Mountains (the Ndundulu population) and two tissue sample from Southern Highlands population, researchers from the National Evolutionary Synthesis Center (NESCent) were able to reconstruct the genetic relationships between these two populations and the kipunji's closest relative (Roberts et al., 2009). They found that the Ndundulu population retains the true Rungwecebus mitochondrial genome while the Southern Highlands population has a distinct mitochondrial haplotype that are basal to the genus Papio and Rungwecebus. This suggests that the Southern Highlands population is a hybrid and might have interbred with baboons while the Ndundulu population did not. The study also suggests that Rungwecebus is a separate genus and is more closely related to Papio than to Lophocebus, Theropithecus, Cercocebus or Mandrillus.
Census shows that there are about 1,100 individuals left in the wild. Of these, only 100 of them lives in Udzungwas Mountains. Losing the population from Udzungwas Mountains means that we will lose the genetic makeup of a true Rungwecebus.
Read more on National Geographic "Africa's rarest monkey may have bred with baboons".
Davenport, TRB. Stanley, WT. Sargis, EJ. De Luca, DW. Mpunga, NE. Machaga, SJ. Olson, LE. 2006. A New Genus of African Monkey, Rungwecebus: Morphology, Ecology, and Molecular Phylogenetic. Science 312(5778) 1378 - 1381 DOI: 10.1126/science.1125631
Roberts, TE. Davenport, TRB. Hildebrandt, KBP. Jones, J. Stanley, WT. Sargis, EJ. Olson, LE. 2009. The biogeography of introgression in the critically endangered African monkey Rungwecebus kipunji. Biology Letters Retrieved November 12, 2009, from http://rsbl.royalsocietypublishing.org/content/early/2009/10/29/rsbl.2009.0741.abstract?papetoc