Yale LogoEvolution dictates several things. A research conducted at the Yale University claims that the consequences of natural selection among 2 generations of existing women has been identified. It foretells that their descendents may be somewhat shorter and chubbier, have lower cholesterol and blood pressure and have their first child earlier in life.

These predictions were based on an examination of women who took part in the famous Framingham Heart Study that started in 1948. The outcome exemplifies the medical importance of evolutionary biology principles; some 150 years after Darwin published The Origin of the Species.

Stephen C. Stearns, senior author of the paper and Edward P. Bass Professor of Ecology and Evolutionary Biology, commented, “The idea that natural selection has stopped operating in humans because we have gotten better at keeping people alive is just plain wrong.”

The reason is that features that facilitate women to have children may carry on being subject to selection. As a first step, the Yale researchers gauged the individual reproductive success of two generations of apparently more than 2000 women who took part in the Framingham study and had reached menopause.

They then analyzed the characteristics that grant reproductive success. After regulating environmental factors like income, education and lifestyle choices such as smoking, the researchers predicted the heritability of features by relating associations among all relatives. They also attuned for the indirect results of selection by gauging the effect the traits have on each other like whether high blood pressure is linked to lower or higher age of sexual maturity.

The statistical analysis allowed researchers to predict which of those traits were likely to be conferred by natural selection upon the third generation of women participating in the Framingham study.

The outcomes illustrated that the impact of natural selection are apparently slow and steady, but incline towards shorter, chubbier women with lower blood pressure and cholesterol and who give birth earlier in life. For example, the women in the third generation of the research are expected to start their periods a month before and enter menopause a month later as compared to their mothers and grandmothers.

Nevertheless, Stearns specify that the pace of alteration driven by natural selection found in this group of women apparently does not vary much from the rates observed in nature.

The research was published in the Proceedings of the National Academy of Sciences.