In the future, globalization will destroy local races and lower rates of rare traits like blue eyes.
According to Stephen Stearns, a Yaleprofessor of ecology and evolutionary biology, before the invention of the bicycle, the average distance between the birthplaces of spouses in England was 1 mile (1.6 kilometers). During the latter half of the 19th century, bikes upped the distance men went courting to 30 miles (48 km), on average. Scholars have identified similar patterns in other European countries. Widespread use of bicycles stimulated the grading and paving of roads, lending credence to the Fugate clan's excuse and making way for the introduction of automobiles. Love's horizons have kept expanding ever since.
Stearns says globalization, immigration, cultural diffusion and the ease of modern travel will gradually homogenize the human population, averaging out more and more people's traits. Because recessive traits dependontwo copies of the same gene pairing up in order to get expressed, these traits will express themselves more rarely, and dominant traits will become the norm. In short, blue eyes and pale skin is out, brown eyes and dark skin is in. Already in the United States, another recessive trait, blue eyes, has grown far less common. A 2002 study by the epidemiologists Mark Grant and Diane Lauderdale found that only 1 in 6 non-Hispanic white Americans has blue eyes, down from more than half of the U.S. white population being blue-eyed just 100 years ago.
The genetic mixing under way in the United States is also happening to a greater or lesser degree in other parts of the world, the researchers said. In some places, unique physical traits tailored to the habitat still confer an evolutionary advantage and thus might not bow out so easily; in other places, immigration happens much more slowly than it does elsewhere. According to Stearns, perfect homogenization of the human race will probably never occur, but in general, Earth is becoming more and more of a melting pot. A population forged from the long-term mixing of Africans, Native Americans and Europeans serves as an archetype for the future of humanity, Stearns said: A few centuries from now, we're all going to look like Brazilians.
Via Dr. Stefan Gruenwald