These theoretical expectations are only   partially consistent with the limited data that we have on gene duplication.   First, comparative studies of nucleotide sequences suggest that although both   copies of a gene may often accumulate degenerative mutations at an   accelerated rate following a duplication event, selection may not be relaxed   completely (14– 16). Second, the frequency of duplicate-gene preservation   following ancient polyploidization events, often suggested to be in the   neighborhood of 30 to 50% over periods of tens to hundreds of millions of years   (17–20), is unexpectedly high.

这些理论假设只是部分地与我们在基因复制方面的有限数据相一致。首先，对核苷酸序列的比较研究表明，尽管一个基因的两个拷贝在重复事件发生后往往会加速积累退行性突变，但选择压力可能不会完全放松（14-16）。第二，在古代多倍体化事件之后，在几千万到数亿年（17-20年）的时间里，重复基因的保存频率出人意料地高，通常被认为大约在30%到50%。