Biswas Kakali, Chakraborty Sandip, Podder Soumita, Ghosh Tapash Chandra
Bioinformatics Centre, Bose Institute, P-1/12, C.I.T. Scheme VII M, Kolkata 700 054, India.
Bioinformatics Centre, Bose Institute, P-1/12, C.I.T. Scheme VII M, Kolkata 700 054, India.
Genomics. 2016 Jul;108(1):11-7. doi: 10.1016/j.ygeno.2016.04.004. Epub 2016 Apr 26.
In mammals, it has long been suggested that brain-specific genes (BSGs) and widely expressed genes (WEGs) have seemingly lower dN/dS ratio than any other gene sets. However, to what extent these genes differ in their dN/dS ratio has still remained controversial. Here, we have revealed lower dN/dS ratio of BSGs than WEGs in human-mouse, human-orangutan, human-chimpanzee and mouse-rat orthologous pair. The significance level of dN/dS ratio difference indicates a trend of decreasing difference as complexity of compared pairs increases. Further studies with the human-mouse pair revealed that, removal of the duplicated genes from both the dataset has nullified this difference which dictates a vital role of duplicated genes in governing the selection pressure. Conclusively, higher paralog number, expression level, and longer regulatory region length of BSGs allow fewer nucleotide substitutions within them. Our results show for the first time to our knowledge lower dN/dS ratio of BSGs than WEGs.
长期以来，人们一直认为在哺乳动物中，脑特异性基因（BSGs）和广泛表达基因（WEGs）的非同义替换率与同义替换率之比（dN/dS）似乎低于其他任何基因集。然而，这些基因在dN/dS比值上的差异程度仍存在争议。在这里，我们揭示了在人-小鼠、人-猩猩、人-黑猩猩和小鼠-大鼠直系同源对中，BSGs的dN/dS比值低于WEGs。dN/dS比值差异的显著性水平表明，随着比较对的复杂性增加，差异有减小的趋势。对人-小鼠对的进一步研究表明，从数据集中去除重复基因消除了这种差异，这表明重复基因在控制选择压力方面起着至关重要的作用。总之，BSGs更高的旁系同源基因数量、表达水平和更长的调控区域长度使得其中的核苷酸替换更少。据我们所知，我们的结果首次表明BSGs的dN/dS比值低于WEGs。
