A scientific team from the Department of Experimental and Health Sciences of the Pompeu y Fabra University of Barcelona (UPF) and the Institute of Evolutionary Biology (IBE), a joint center of the UPF and the CSIC, has discovered the ultimate genetic causes of aging human . This aging process poses a challenge to the public health system and is a scientific enigma that fascinates evolutionary biologists. So far no theory has managed to explain its causes and it is not clear what its global impact on human health will be.
The new study has used all the data accumulated during a decade of research on the genetic bases of complex diseases – from Parkinson’s to cancer to diabetes – to test different evolutionary theories of old age.
Until now, research had focused on experimental models with the fruit fly and the conclusions were often contradictory. But currently the large amount of data available on the relationship between genotype (the set of genes that exist in the cell nucleus of each individual) and phenotype (the way in which these genes are expressed when interacting with the environment) has led to carry out these tests in humans. Information from large international databases such as the European Genome Phenome Archive (EGA), a joint project between the European Bioinformatics Institute (EBI), in Cambridge, and the Center for Genomic Regulation (CRG) in Barcelona, is available to the scientific community.
Arcadi Navarro, former ICREA research professor at UPF, has co-led the study in which the results of some 3,000 investigations with more than 2,500 markers on a total of 120 diseases have been examined. According to Navarro, “the ability to find out if an individual is healthy or will develop a disease throughout life has greatly improvedas data has been collected. “
For starters, scientists have considered whether the markers for each disease have an effect on youth or old age. The distinction is very important sinceif a mutation has harmful consequences in old age, our genes will have already been passed on to our offspring and natural selection will not be able to act. The results of this study show that the frequency and effect of mutations that cause disease in old age are higher than those that cause disease at a young age. “We have found aevolutionary threshold at 40-50 years, biologically significant age because it limits the reproductive period“says Navarro.
Bioinformatics studies carried out by Juan Antonio Rodríguez, first author of the work, have also shown thatthere are mutations that are beneficial in youth but become harmful in old age. But “being positive during the reproductive period, they will be favored by natural selection and passed on to the offspring, and therefore they can hardly be suppressed,” he explains. “Physical decline in old age could be the evolutionary price we have to pay to be healthy at the age of having children“says Elena Bosch, co-leader of the study and group leader at the IBE. For example, a medicine that we give to a child can have negative effects when he is old. On the contrary, alsoit can happen that a very sick person in childhood, if he survives, has iron health in old age. The research results are published in the journalNature Ecology & Evolution.
