Mean dN/dS ratios for region groups.

*454 proteins contain poly-Q tracts of four or more glutamines in humans. However, this number excludes 41 human proteins without assigned homologs in either mouse or rat, which served as the references for estimating the dN/dS ratios. Additionally, the dN/dS ratios for some regions flanking the poly-Q tracts were not available by PAML estimation. The dN/dS ratios were calculated for a region including 33 amino acids on either side of the repeat and excluding the repeat.人类体内共有454种蛋白质含有包含4个及以上谷氨酰胺残基的多谷氨酰胺序列（poly-Q tract）。但该统计结果未纳入41种在小鼠或大鼠中无明确同源蛋白的人类蛋白质，此类蛋白曾作为估算dN/dS比值的参照样本。此外，通过PAML估算无法获得多谷氨酰胺序列侧翼部分区域的dN/dS比值。本次计算dN/dS比值的区域为该重复序列两侧各延伸33个氨基酸残基的区段，且不包含该重复序列本身。