article_snippet.sent: This can make it difficult to unpick the influence of environment over genetics.
article_snippet.sent: This percentage is called heritability.
article_snippet.sent: These latest results from UK data confirm the trends found in previous research carried out in the US.
article_snippet.sent: We and others have demonstrated consistent genetic influences on all measurable aspects of We personalities,' said These latest results from UK data. '
article_snippet.sent: Professor Tim Spector is the Professor of Genetic Epidemiology at King's College London .
article_snippet.sent: Victoria Vazquez also contributed to this article.