Using autosomal internecine non repetitive sequences from the human genome, researchers were able to estimate divergence times on the molecular clock for humans and chimpanzees, and the point at which gorillas broke off from their shared branch. In retrospect, this study now confirms the current working model, in addition to confirming that humans and chimps have about a 1% DNA difference. However, using tree parsimony based on independent analysis of 22 of the 53 segments, the researchers also estimated the effective population of the Pan/Homo common ancestor to be larger than previously thought. By analyzing the 53 segments in combination with 37 protein genes, researchers estimated that this effective population was somewhere between 52,000 and 96,000 individuals, as opposed to the 10,000 that had previously been suggested. Given this, the researchers conclude that the effective populations of Homo experienced a drastic reduction post-Pan split.
Source: Am. J. Human Gen. (2001)