Researchers have discovered that some people have a rare genetic mutation that decreases their cells' use of a particular growth hormone: insulin-likegrowthfactor 1 (IGF1).
If you look in the normal population and ask what fraction of people have [a defect in methylation in the gene encoding insulin-likegrowthfactor 2] it's about 5 percent.
如果你观察普通人群，调查多少比例的人有[胰岛素类生长因子2基因编码甲基化的缺陷]，大概是百分之5。
3
Cows, like humans, produce insulin-likegrowthfactor in response to growth hormones and release it into the blood, and the protein makes its way into their milk.