Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
Nature. 2011 Oct 19;478(7369):343-8. doi: 10.1038/nature10532.
Changes in gene expression are thought to underlie many of the phenotypic differences between species. However, large-scale analyses of gene expression evolution were until recently prevented by technological limitations. Here we report the sequencing of polyadenylated RNA from six organs across ten species that represent all major mammalian lineages (placentals, marsupials and monotremes) and birds (the evolutionary outgroup), with the goal of understanding the dynamics of mammalian transcriptome evolution. We show that the rate of gene expression evolution varies among organs, lineages and chromosomes, owing to differences in selective pressures: transcriptome change was slow in nervous tissues and rapid in testes, slower in rodents than in apes and monotremes, and rapid for the X chromosome right after its formation. Although gene expression evolution in mammals was strongly shaped by purifying selection, we identify numerous potentially selectively driven expression switches, which occurred at different rates across lineages and tissues and which probably contributed to the specific organ biology of various mammals.
基因表达的变化被认为是许多物种表型差异的基础。然而，直到最近，由于技术限制，大规模的基因表达进化分析才得以实现。在这里，我们报告了来自 10 个物种的 6 个器官的聚腺苷酸化 RNA 的测序，这些物种代表了所有主要的哺乳动物谱系（胎盘动物、有袋动物和单孔目动物）和鸟类（进化的外群），目的是了解哺乳动物转录组进化的动态。我们表明，由于选择压力的不同，基因表达进化在器官、谱系和染色体之间存在差异：在神经系统中变化缓慢，在睾丸中变化迅速，在啮齿动物中比在类人猿和单孔目动物中变化缓慢，并且在 X 染色体形成后迅速变化。尽管哺乳动物的基因表达进化受到纯化选择的强烈影响，但我们确定了许多潜在的受选择驱动的表达开关，这些开关在不同的谱系和组织中以不同的速度发生，这可能有助于各种哺乳动物的特定器官生物学。
