PARC Departmental Papers


Natural Selection in a Contemporary Human Population

Document Type

Journal Article

Date of this Version



Authors: Sean G. Byars, Douglas Ewbank, Diddahally R. Govindaraju, and Stephen C. Stearns. Published online before print October 26, 2009, doi: 10.1073/pnas.0906199106 PNAS January 26, 2010 Vol. 107, No. Supp. 1, P 1787-1792 PARC Working Paper Series, 03, 2010


Our aims were to demonstrate that natural selection is operating on contemporary humans, predict future evolutionary change for specific traits with medical significance, and show that for some traits we can make short-term predictions about our future evolution. To do so, we measured the strength of selection, estimated genetic variation and covariation, and predicted the response to selection for women in the Framingham Heart Study, a project of the National Heart, Lung, and Blood Institute and Boston University that began in 1948. We found that natural selection is acting to cause slow, gradual evolutionary change. The descendants of these women are predicted to be on average slightly shorter and stouter, to have lower total cholesterol levels and systolic blood pressure, to have their first child earlier, and to reach menopause later than they would in the absence of evolution. Selection is tending to lengthen the reproductive period at both ends. To better understand and predict such changes, the design of planned large, long-term, multicohort studies should include input from evolutionary biologists.


evolutionary rates, heritability, Homo sapiens, medical traits



Date Posted: 01 February 2010

This document has been peer reviewed.