Spatial distribution of selection pressure on a protein deriving its adaptation to the environment based on the hierarchical Bayesian model

2014 Fiscal Year Final Research Report

• Project/Area Number: 24570249
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Evolutionary biology
• Research Institution: Kochi University
• Principal Investigator: WATABE Teruaki 高知大学, 教育研究部医療学系, 講師 (90325415)
• Co-Investigator(Kenkyū-buntansha): KISHINO Hirohisa 東京大学, 農学生命科学研究科, 教授 (00141987)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 分子進化 / タンパク質多様化圧

Outline of Final Research Achievements

Proteins adapt to novel environments and/or gains functions by substitution in amino-acid sequences. Therefore, mutations in protein-coding genes occur under the selection pressure, the strength and character of which may vary among the regions of the protein. Thus, the spatial distribution of selection pressure provides information on the adaptive evolution of the protein. To detect the distribution, we developed a hierarchical Bayesian model. The Potts model describes the prior distribution of spatial aggregation of selection pressure. The hyper-parameters that define the strength and range of spatial clustering are estimated by maximizing the marginal likelihood. We applied the method to historical data on the influenza hemagglutinin protein, comparing the estimated spatial distribution to that of antigenic sites A-E. The amino-acid residues with higher substitution-rate ratios, representing diversifying selection pressure, overlapped the antigenic sites.

Free Research Field

分子進化生物学