Gibbs P E, Dugaiczyk A
Department of Biochemistry, University of California, Riverside 92521.
Proc Natl Acad Sci U S A. 1994 Apr 12;91(8):3413-7. doi: 10.1073/pnas.91.8.3413.
The closely related serum albumin, alpha-fetoprotein, and vitamin D-binding proteins are derived from a common ancestor, which itself was the result of a triplication of an ancestral gene. We have aligned the sequences of these proteins against themselves to assess the degree to which the ancestral 3-fold symmetry has been retained; in a dot plot, relics of the molecular symmetry appear as a series of alignments parallel to the main diagonal. The decay of internal symmetry reflects the rate of change of a gene in a single line of evolutionary descent. We examined 11 serum albumins, 2 ceruloplasmins, 3 alpha-fetoproteins, and 3 vitamin D-binding proteins. We have found that ceruloplasmin evolves at the same rate in human and rat, whereas albumin, alpha-fetoprotein, and vitamin D-binding protein evolve at different rates. The human genes had the highest alignment scores, indicating the most preserved ancestral features. We conclude that the molecular clock may run at different rates for the same gene in different species.
密切相关的血清白蛋白、甲胎蛋白和维生素D结合蛋白源自一个共同祖先，而这个共同祖先本身是一个原始基因经三次重复的产物。我们已将这些蛋白质的序列与其自身进行比对，以评估原始的三重对称性保留的程度；在点阵图中，分子对称性的遗迹表现为一系列与主对角线平行的比对。内部对称性的衰退反映了在单一进化谱系中一个基因的变化速率。我们研究了11种血清白蛋白、2种铜蓝蛋白、3种甲胎蛋白和3种维生素D结合蛋白。我们发现，铜蓝蛋白在人和大鼠中的进化速率相同，而白蛋白、甲胎蛋白和维生素D结合蛋白的进化速率不同。人类基因具有最高的比对分数，表明其保留了最多的原始特征。我们得出结论，对于不同物种中的同一个基因，分子钟可能以不同速率运行。
