Naylor G J, Gerstein M
Department of Zoology and Genetics, Iowa State University, Ames, IA 50011, USA.
J Mol Evol. 2000 Sep;51(3):223-33. doi: 10.1007/s002390010084.
Variability profiles measured over a set of aligned sequences can be used to estimate evolutionary freedom to vary. Differences in variability profiles between clades can be used to identify shifts in function at the molecular level. We demonstrate such a shift between the alpha and beta subunits of hemoglobin. We also show that the variability profiles for myoglobin are different between whales and primates and speculate that the differences between the two clades may reflect a shift associated with the novel oxygen storage demands in the lineage leading to whales. We discuss the relationship between sequence variability and "evolutionary opportunity" and explore the utility of Maynard Smith's multidimensional evolutionary opportunity space metaphor for exploring functional constraints, genetic redundancy, and the context dependency of the genotype-phenotype map. This work has implications for quantitatively defining and comparing protein function. Supplementary data is available from bioinfo.mbb.yale. edu/align.
在一组比对序列上测量得到的变异性图谱可用于估计变异的进化自由度。不同进化枝之间变异性图谱的差异可用于识别分子水平上的功能转变。我们展示了血红蛋白α亚基和β亚基之间的这种转变。我们还表明，鲸类和灵长类动物的肌红蛋白变异性图谱不同，并推测这两个进化枝之间的差异可能反映了与鲸类谱系中新型氧气储存需求相关的转变。我们讨论了序列变异性与“进化机会”之间的关系，并探索了梅纳德·史密斯的多维进化机会空间隐喻在探索功能限制、基因冗余以及基因型-表型图谱的上下文依赖性方面的效用。这项工作对定量定义和比较蛋白质功能具有启示意义。补充数据可从bioinfo.mbb.yale.edu/align获取。
