A groundbreaking study conducted by the Institute of Evolutionary Biology (IBE) and Pompeu Fabra University (UPF) has revealed a remarkable genetic contribution from Denisovans to modern humans. This latest research has identified a genetic variant that is closely linked to zinc regulation, which may have played a crucial role in the adaptation of ancestral human populations to cold environments. Published in PLoS Genetics, the study also suggests that this genetic adaptation may have increased the susceptibility to neuropsychiatric disorders in modern humans.
The migration of modern humans out of Africa around 60,000 years ago led to encounters with the Denisovans in Asia. These encounters likely involved a mix of conflict, collaboration, and interbreeding, resulting in the retention of genetic variants of Denisovan origin in the modern human genome.
The research team, led by the Institute of Evolutionary Biology (IBE) and Pompeu Fabra University (UPF), has now identified one of the most widespread traces of Denisovan genetic heritage in modern humans. They have discovered that this genetic adaptation played a role in the adaptation of ancestral human populations to cold environments.
The observed genetic variant, which is involved in zinc regulation and cellular metabolism, may also have predisposed modern humans to psychiatric disorders such as depression and schizophrenia.
Understanding how adaptation has shaped the current genetic diversity in human populations is a topic of great interest in evolutionary genetics. The research team identified an adaptive variant in modern human populations that closely resembled the genome of the extinct Denisovans. They determined that this genetic variant resulted from interbreeding with Denisovans rather than Neanderthals.
The variant in question appears to have provided a selective advantage for humans, leading to its spread and prevalence in current populations. The researchers hypothesized that this genetic variation affected the transport of zinc within cells and its role in adapting to the cold. To investigate this further, they collaborated with a team specializing in the movement of intracellular zinc.
Zinc is an essential trace element for human health, serving as a messenger for information transfer within cells and between cellular compartments. The observed genetic variant alters the balance of zinc within cells, potentially promoting metabolic changes. These changes affect the endoplasmic reticulum and mitochondria of cells, providing a possible metabolic advantage in coping with cold climates.
In addition to its role in cellular metabolism, zinc transport is also involved in nervous system excitability and mental health. The researchers found that the genetic variant in the zinc transporter associated with a higher predisposition to psychiatric disorders such as anorexia nervosa, hyperactivity disorder, autism spectrum disorder, bipolar disorder, depression, obsessive-compulsive disorder, and schizophrenia.
While the genetic variant originated from interbreeding between Denisovans and modern humans in Asia, it has spread to European and Native American populations. It is found in populations across the globe, except for African populations, where it is less frequent.
The researchers believe that this Denisovan genetic adaptation has the broadest geographical scope discovered so far. Unlike other Denisovan variants that are specific to certain populations, this variant has impacted populations outside of Africa worldwide. Further research, including animal models, may shed light on the link between this genetic variant and mental illnesses.
In conclusion, the study highlights the significant contribution of Denisovan genetic heritage to modern humans. The identified genetic variant related to zinc regulation may have provided an evolutionary advantage in adapting to cold environments. However, it may have also increased the susceptibility to neuropsychiatric disorders. The findings underscore the complex and dynamic interactions between ancient human populations and their genetic legacies that continue to shape our genetic diversity today.