Your mental illnesses may be a result of ancient cross-species fornication, a study has found

There is nothing that affects mental health quite like the combination of soaring inflation, a planet in decline, and ongoing wars; it's no wonder that mental health issues appear to be increasing in humans. However, there might be another hidden factor influencing the development of psychological disorders in us: our primitive instincts.

The story of human evolution is an intricate tapestry woven with a ton of interbreeding with other hominid species. Among these interactions, one stands out — an ancient meeting between modern humans and the Denisovans, an extinct subspecies of archaic humans who lived on Earth until at least 30,000 years ago.

Most accounts suggest that modern humans left Africa around 60,000 years ago during the "Out-of-Africa" event, eventually encountering the Denisovans in Asia. These interactions led to crossbreeding and the integration of Denisovan genetic material into the modern human genome.

While this encounter may have been beneficial in some ways, recent research has also revealed how this ancient genetic legacy may have a lasting impact on the mental health of modern humans, including conditions like depression and autism.

A team of researchers, led by Elena Bosch and Rubén Vicente, has identified one of the most widespread remnants of Denisovan heritage in modern humans. This particular genetic adaptation helped early Homo sapiens populations adapt to cold climates and is related to the regulation of zinc in our bodies.

Zinc is a crucial trace element for human health, playing a significant role in transmitting information within and between cells. Vicente's team found that the observed Denisovan genetic variant alters zinc balance within cells, changing our metabolism to help us better withstand harsh, cold environments.

Zinc transport plays a vital role in the nervous system and overall mental health. However, the Denisovan genetic variant found in the zinc transporter is also linked to a higher susceptibility to various psychiatric disorders. These include widespread conditions such as depression, obsessive-compulsive disorder, schizophrenia, anorexia nervosa, attention deficit hyperactivity disorder, autism spectrum disorder, and bipolar disorder.

Although the Denisovan genetic adaptation originated in Asia, it is not limited to a specific geographical region. This variant has spread to European and Native American populations and is now present worldwide. It is one of the most widespread adaptations inherited from the Denisovans, present in 4-6% of non-African modern humans.

This intriguing discovery provides valuable insights into the complex history of our species and its potential impact on our well-being today. Future research, including studies using animal models, may help unravel the connection between this genetic legacy and mental health disorders, ultimately deepening our understanding of the human condition.

The findings of this study have been published in PLOS Genetics and can be accessed here.