In addition, even if there is a real effect here, it is so small, and the interactions so complex, that it&#x27;s probably useless.<p>For example, even if this neanderthal gene happens to causally affect depression by 1%, that pathway might be something like<p>gene =&gt; slightly wider shoulders =&gt; that body structure is slightly more or less likely to lead to certain life outcomes, like marrying early or getting promoted or getting targeted by pickpockets =&gt; change in depression risk<p>As a result, the gene might currently lead to a 1% increase in depression risk, but in a few years it might do the opposite, if things change in the surrounding culture and those intermediary steps behave a little differently.