Evolutionary opener from Space Odyssey 2001.
You may think humans haven’t evolved for millennia, but new genomics data describes the past 40,000 years as a period of supercharged human evolutionary change, driven by exponential population growth and cultural shifts.
A team led by University of Wisconsin anthropologist John Hawks has estimated that positive selection just in the past 5,000 years alone ~ dating back to the Stone Age ~ has occurred at a rate roughly 100 times higher than any other period of human evolution.
Many of the new genetic adjustments are driven by changes in the human diet brought on by the advent of agriculture, and resistance to epidemic diseases that became major killers after the growth of human civilizations.
"In evolutionary terms, cultures that grow slowly are at a disadvantage, but the massive growth of human populations has led to far more genetic mutations," says Hawks. "And every mutation that is advantageous to people has a chance of being selected and driven toward fixation. What we are catching is an exceptional time."
According to a University of Wisconsin press release:
While the correlation between population size and natural selection was a core premise of Charles Darwin, Hawks says the ability to bring quantifiable evidence to the table is a new and exciting outgrowth of the Human Genome Project.The biggest new pathway for selection relates to disease resistance, Hawks says. As people starting living in much larger groups and settling in one place roughly 10,000 years ago, epidemic diseases such as malaria, smallpox and cholera began to dramatically shift mortality patterns in people.
The researchers identify recent genetic change by finding long blocks of DNA base pairs that are connected. Because human DNA is constantly being reshuffled through recombination, a long, uninterrupted segment of LD is usually evidence of positive selection. Linkage disequilibrium decays quickly as recombination occurs across many generations, so finding these uninterrupted segments is strong evidence of recent adaptation, Hawks says.
Employing this test, the researchers found evidence of recent selection on approximately 1,800 genes, or 7 percent of all human genes.
Click here for the Daily Galaxy article.