To grasp the nature of the problem, we need to examine how humans are made at the molecular level, and contrast our constitution with that of other species that we often call “rudimentary,” such as unicellular organisms. This analysis leads us to examine proteins – our cellular building blocks and the executors of biologicalfunctions – across vastly different species.
为了抓住这一问题的本质，我们需要在分子水平上考察一下人类的构成，把我们与那些我们称之为“原始”的物种（比如单细胞生物）做个比较。该分析让我们考察大量不同物种体内的蛋白质，即组成我们的分子基石和生物功能的执行者。拥有同一祖先的不同物种的蛋白质，即所谓的“同源体”，为我们提供了很好的比较基准。