 It was concluded that the Olduvai domain appears to have a role in neural stem cell proliferation, since this proliferation seems to be the major contributor to lobe surface area while also explaining the effects of Olduvai dosage that could not be explained by brain region measurements.Corroborating this are stem cell cultures that have also shown Olduvai's proliferative effects neuronal stem cells.However, Olduvai also had effects on cortical thickness that appeared to be the result of mature neuron cell divisions, corroborated by higher neuron numbers in primates being associated with Olduvai copy number.