中文摘要：

与比较基因组学途径，我们评估了富有地被表示的前 ons 的保存的进化特征，中等或在哺乳动物低层。用非编码的区域和假基因，作为控制，顺序身份， phastCons 和 Ka/Ks，分析被执行，当高丰富的前 ons 高度被保存，我们的结果显示出那，次要、低的前 ons 也在进化显示出保守特征。我们的调查结果建议有在有机体的 transcriptome 组成不同种类的一个大比例的更少的丰富的前 ons 在功能的限制下面并且可能在在有机体的进化充实生物复杂性起某些作用。

英文摘要：

With comparative genomics approaches, we evaluated the evolutionary characteristics of conservation of exons which are expressed abundantly, moderately or lowly in mammals. Using non-coding regions and pseudogenes as controls, sequence identity, phastCons and KalKs analyses were carried out and our results showed that as the exons of high abundance are highly conserved, the minor and low exons also showed conservative characteristics in evolution. Our findings suggested that the exons with less abundance which constitute a large proportion of distinct species in transcriptome of organisms are under functional constraint and might play certain roles in enriching biological complexity in the evolution of organisms.