Alzheimer's disease – woe from wit?
Senile dementia was explained by the appearance of the human mind
The evolution of the human mind is to blame for Alzheimer's disease, Chinese biologists say. The most common form of senile dementia arose simultaneously with the increased capabilities of the brain. A study on this topic is presented in the journal bioRxiv (Hang Zhou et al., A Chronological Atlas of Natural Selection in the Human Genome during the Past Half-million Years), and it is briefly reported by Nature News & Comment (Alzheimer's origins tied to rise of human intelligence).
Geneticist Kun Tang from the Shanghai Institute of Biological Sciences suggested that Alzheimer's disease arose because the aging brain stopped satisfying the powerful needs of the enhanced mind. It is known that senile dementia of the Alzheimer's type occurs only in Homo sapiens – it does not occur even in the closest human relatives among primates.
To find the origins of the disease in human evolution, Tan and his colleagues studied the genomes of 90 people of Asian, European and African descent. Scientists managed to separate fragments of DNA that changed for historical and demographic reasons from those whose structure was determined by natural selection.
As a result, scientists have found six genes associated with brain development. Between 200 and 50 thousand years ago (when Homo sapiens appeared), these genes underwent a number of changes, which, in particular, increased the number of relationships between neurons. However, the authors of the article state that the same six genes are responsible for the development of Alzheimer's disease.
Portal "Eternal youth" http://vechnayamolodost.ru28.05.2015