In a recent paper in the journal Science, Venter and his colleagues ___1___ that they had created the smallest living and reproducing organism. Their creation is a simple cell, with only the genes that are essential for life; it is larger only than those found in viruses and other entities that rely on hosts(寄主) for ___2___ functions.
Venter and his team created their organism through a process of ___3___ and error. They began by using their knowledge of biology to deduce the minimum set of genes that would be required for life. However, that approach ___4___.
The most important result of the Venter team's work was to ___5___ how little we know about the basic biology of life. Most of the 473 genes take care of housekeeping: They make proteins, keep DNA in good repair, and are ___6___ for the cell's membrane (薄膜) and cytoplasm (细胞质). But there are 149 genes whose function is unknown. In other words, the purpose of nearly one-third of the genes, which needed to keep the organism ___7___, and reproducing remains a ___8___.
Of the 149 genes with unknown functions, 70 have a structure that at least hints at their role in the cell. But we know nothing about the other 79, except that in these organisms, in this environment, life is ___9___ without them.
All of this implies many exciting discoveries ahead. And yet, when it comes to practical, commercial objectives, the news is ___10___ more sobering.