Trabesinger-Ruef N, Jermann T, Zankel T, Durrant B, Frank G, Benner S A
Department of Chemistry, ETH, Zurich, Switzerland.
FEBS Lett. 1996 Mar 18;382(3):319-22. doi: 10.1016/0014-5793(96)00191-3.
Bovine seminal ribonuclease (RNase) diverged from pancreatic RNase after a gene duplication ca. 35 million years ago. Members of the seminal RNase gene family evidently remained as unexpressed pseudogene for much of its evolutionary history. Between 5 and 10 million years ago, however, after the divergence of kudu but before the divergence of ox, evidence suggests that the pseudogene was repaired and expressed. Intriguingly, detailed analysis of the sequences suggests that the repair may have involved gene conversion, transfer of information from the pancreatic gene to the RNase pseudogene. Further, the ratio of non-silent to silent substitutions suggests that the pancreatic RNases are divergently evolving under functional constraints, the seminal RNase pseudogenes are diverging under no functional constraints, while the genes expressed in the seminal plasma are evolving extremely rapidly in their amino acid sequences, as if to fulfil a new physiological role.
牛精浆核糖核酸酶（RNase）在约3500万年前基因复制后从胰腺核糖核酸酶分化而来。在其进化历史的大部分时间里，精浆核糖核酸酶基因家族的成员显然一直是未表达的假基因。然而，在500万到1000万年前，在捻角羚分化之后但牛分化之前，有证据表明该假基因被修复并表达。有趣的是，对序列的详细分析表明，修复可能涉及基因转换，即信息从胰腺基因转移到核糖核酸酶假基因。此外，非同义替换与同义替换的比率表明，胰腺核糖核酸酶在功能限制下呈发散性进化，精浆核糖核酸酶假基因在无功能限制下发生分化，而在精浆中表达的基因在其氨基酸序列中进化得极快，仿佛是为了履行一种新的生理功能。
