Modern humans inherited a gene from Denisovans, an extinct species of ancient humans, through interbreeding tens of thousands of years ago. This genetic adaptation may have left modern humans predisposed to certain mental health issues, including depression, according to a study by researchers from Spain.
The gene in question, SLC30A9, is responsible for regulating zinc transportation across cell membranes. Zinc is vital for healthy growth and the proper functioning of the neurological and immune systems. Researchers discovered that a variant of this gene is more common in East Asian populations and likely evolved through positive selection. Through genomic analysis, scientists found that this genetic variant came from the interbreeding of modern humans with archaic humans in the past, possibly the Denisovans.
Lab experiments showed that this genetic variation affects how some cellular structures, including mitochondria, handle zinc, potentially influencing metabolism. The same SLC30A9 variation has previously been linked to a greater risk of depression and other mental disorders.
The relationship between this genetic adaptation and mental health is likely due to the role of zinc in managing nervous system excitability and other associations with mental health. Further research is needed to explore this connection.
This study highlights the complexity of human genetics and the potential effects of ancient genetic adaptations on modern health and well-being.
