Analysis of recombination hot regions based on inference of intensity of recombination at nucleotide level in pathogenic bacterial species

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K21554
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Genome biology; Genetics/Chromosome dynamics
• Research Institution: National Institute of Infectious Diseases (2016-2018); Kurume University (2015)
• Principal Investigator: Yahara Koji 国立感染症研究所, 薬剤耐性研究センター, 主任研究官 (70542356)
• Research Collaborator: Falush Daniel Max Planck Institute ; Didelot Xavier Imperial College London ; Maiden Martin University of Oxford ; Sheppard Samuel Swansea University ; Kobayashi Ichizo 東京大学
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 組換え / 進化 / 細菌 / ゲノム / 自然選択 / 病原性 / 集団遺伝 / 情報

Outline of Final Research Achievements

This project elucidated landscape of realized homologous recombination and recombination “hot” region with elevated rates relative to the genome average in 11 human pathogens of major public health importance. It gave answers to the following questions: (A) Do virulence genes show elevated rates of recombination? (B) Do genomic regions carrying recurrent amino acid changes under diversifying selection show elevated rates of recombination? (C) Are there shared recombination “hot” or “cold” genes that show consistently high or low recombination rate among the species? (D) Is horizontal gene transfer between species related to the recombination “hot” region? Furthermore, another methodological improvement and its application to Helicobacter pylori enabled elucidation of novel population structure and amino acid changes that were important during its evolution.

Free Research Field

微生物集団ゲノム科学、進化学、バイオインフォマティクス、生物統計学

Academic Significance and Societal Importance of the Research Achievements

1 塩基単位の高解像度での組換えのランドスケープとホット領域を、組換え率の最も高い種から低い種まで11種にわたって明らかにしたのは、これが全生物で初めてであった。また、生物学の長年の関心事であるアミノ酸置換率と組換え率の関係について、微生物ゲノムの中から初めて定量的なエビデンスを示すことができた。いずれも、生物学一般にとって意義深い成果だと言える。公衆衛生に重要な病原細菌種を対象とした点で、医学的にも意義深い。