Alzheimer’s Origins Tied to Rise of Human Intelligence: Factors that drove the evolution of our intellectual capacity are also implicated in the memory disorder
- by Nala Rogers
Alzheimer’s disease may have evolved alongside human intelligence, researchers report in a paper posted this month on BioRxiv. The study finds evidence that 50,000 to 200,000 years ago, natural selection drove changes in six genes involved in brain development. This may have helped to increase the connectivity of neurons, making modern humans smarter as they evolved from their hominin ancestors. But that new intellectual capacity was not without cost: the same genes are implicated in Alzheimer’s disease.
Kun Tang, a population geneticist at the Shanghai Institutes for Biological Sciences in China who led the research, speculates that the memory disorder developed as ageing brains struggled with new metabolic demands imposed by increasing intelligence. Humans are the only species known to develop Alzheimer’s; the disease is absent even in closely related primate species such as chimpanzees.
Tang and his colleagues searched modern human DNA for evidence of this ancient evolution. They examined the genomes of 90 people with African, Asian or European ancestry, looking for patterns of variation driven by changes in population size and natural selection” (read more).
(Source: Scientific American)