In the past 2,000-3,000 years, for example, Europeans have undergone changes in the gene for a protein that moves potassium ions in and out of nerve cells and taste buds.

• 举例说明，在过去的2,000到3,000年间，欧洲人经历了一种蛋白质基因的变化，这种蛋白质负责把钾离子从神经元细胞和味蕾内搬进搬出。