U.S. researchers said that the future may be more petite women, more fullness, heart healthy, reproductive period is longer, and they would be these characteristics to their offspring. The evidence suggests that human evolution is still continuing. Research results published in the "U.S. National Academy of Sciences" on.
Medical advances mean premature death of many people in the past will now live to a ripe old age, which many people believe that natural selection will not affect humans, we have stopped evolution.
However, Yale University biology professor Stephen Stearns said that despite medical advances help people no longer depend on the life of the human genome, but there are still large differences in fertility, they want to know, that women could birth a more whether such a feature many children can be passed to future generations.
To find out, Stearns and colleagues studied the U.S. federal government Fuming John Heart Study data, the program records of the Massachusetts town of 14,000 residents Fuming John since 1948, medical records, during this period Many families across the three generations.
Study the research team has been through menopause and can not stop having the 2238 women. They tested the women's weight, height, blood pressure, cholesterol and other characteristics, in order to understand whether these factors the number of child-rearing with them closely. The researchers also control the social and cultural factors to calculate these characteristics of natural selection in shaping the role of areas.
The results show that compared to tall, slender women, more petite, but full of women's reproductive ability is usually stronger, more children; lower blood pressure, lower cholesterol, women also have more children; in younger When women give birth to their first child, and later the arrival of menopause women have more children. Surprisingly, these features are passed to their daughters, their daughters have more children.
The researchers predicted that if this trend continued for 10 generations, in 2409, women are shorter than 2 cm, weight 1 kg, give birth to a child's time will be the first 5 months in advance, the arrival time of menopause be delayed 10 months.
What is hard to say choose these characteristics, it is difficult to know whether these characteristics are passed through the women's genes. However, researchers controlled for a number of social and cultural factors, so this result shows that it is genetic rather than cultural role in evolution. Stearns noted that, despite cultural differences also affect human reproduction, but still affects the biological properties of human evolution, this is very interesting.
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