translation.en: It's been a 15-year quest just to get to the starting point now to be able to answer those questions, because it's very difficult to eliminate multiple genes from a cell.
translation.zh: 经过15年的探索 现在才达到了问题的出发点 才有可能回答那些问题 因为要将多个基因从细胞中去除 是非常困难的