Warnecke Tobias, Wang Guang-Zhong, Lercher Martin J, Hurst Laurence D
Department of Biology & Biochemistry, University of Bath, UK.
BMC Evol Biol. 2009 Aug 7;9:193. doi: 10.1186/1471-2148-9-193.
A prerequisite for a duplication to spread through and persist in a given population is retaining expression of both gene copies. Yet changing a gene's dosage is frequently detrimental to fitness. Consequently, dosage-sensitive genes are less likely to duplicate. However, in cases where the level of gene product is controlled, via negative feedback, by its own abundance, an increase in gene copy number can in principle be decoupled from an increase in protein while both copies remain expressed. Using data from the transcriptional networks of E. coli and S. cerevisiae, we test the hypothesis that genes under negative auto-regulation show enhanced duplicability.
Controlling for several known correlates of duplicability, we find no statistically significant support in either E. coli or S. cerevisiae that transcription factors under negative auto-regulation hold a duplicability advantage over transcription factors with no auto-regulation.
Based on the analysis of transcriptional networks in E. coli and S. cerevisiae, there is no evidence that negative auto-regulation has contributed, on a genome-wide scale, to the variability in gene family sizes in these species.
一个重复序列要在特定种群中传播并持续存在，其前提条件是两个基因拷贝都保持表达。然而，改变基因剂量常常对适应性有害。因此，剂量敏感基因不太可能发生重复。但是，在基因产物水平通过负反馈由其自身丰度控制的情况下，基因拷贝数的增加原则上可以与蛋白质增加脱钩，同时两个拷贝仍保持表达。利用大肠杆菌和酿酒酵母转录网络的数据，我们检验了负自调节下的基因具有更高可重复性的假设。
在控制了几个已知的与可重复性相关的因素后，我们发现在大肠杆菌和酿酒酵母中，均没有统计学上的显著证据支持负自调节下的转录因子比无自调节的转录因子具有可重复性优势。
基于对大肠杆菌和酿酒酵母转录网络的分析，没有证据表明负自调节在全基因组范围内促成了这些物种基因家族大小的变异性。
