Addiction and Depression Blamed on Neanderthal Genes

Results from a comprehensive study indicate that mental disorders, blood clotting, and addictive behaviors have been inherited from Neanderthal genes to modern humans. Now, if someone is a smoker or depressed, they can blame their Neanderthal ancestors. According to AFP, scientists announced in 2010 that the ancestors of modern humans (Homo sapiens) living in Africa encountered another type of early human known as Neanderthals after migrating to Europe and Asia, and interbred with them. Currently, 1 to 4 percent of the genes in modern humans trace back to Neanderthals. In this study, Neanderthal DNA was examined in the genomes of about 28,000 adult individuals of European descent; the medical histories of these individuals demonstrated the 'subtle, yet significant' impact of Neanderthal genes on modern humans. John Capra, an assistant professor of biological sciences at Vanderbilt University, states: 'Our main finding is that Neanderthal DNA influences clinical traits in modern humans. We found a relationship between Neanderthal DNA and many traits including immune, skin, neurological, psychological, and fertility diseases.' This research also shows that modern human DNA includes 135,000 gene variants related to Neanderthals, who lived on Earth about 30,000 years ago. Scientists found that these genes increase the risk of 12 diseases, including depression, heart attack, and especially nicotine addiction. Psychological and neurological effects are observed in many individuals with Neanderthal DNA. Some gene variants increase depression while others decrease it. Certain Neanderthal gene variants enhance blood clotting. This was beneficial for rapid wound healing and preventing pathogens from entering the body. However, today, individuals whose blood clots more quickly are at greater risk for stroke, pulmonary blockage, and pregnancy complications. Neanderthals lived in Europe and Western Asia for about 200,000 years before the arrival of modern humans. Scientists believe that modern humans retained some Neanderthal DNA during evolution that was advantageous in overcoming environmental challenges outside Africa. Nevertheless, many of these genes may not be beneficial in today's modern environments. Another study published in January in the journal 'Human Genetics' found evidence of a connection between Neanderthal genes and certain immune disorders, allergies, and shortness of breath. This research was published in the February 12 issue of the journal 'Science.'