Shedding light on genome evolution of a 220-million-year old's cockroach friend: Blattabacterium cuenoti

2019 Fiscal Year Annual Research Report

• Project/Area Number: 18K14767
• Research Institution: Okinawa Institute of Science and Technology Graduate University
• Principal Investigator: ブギーニョン トマ 沖縄科学技術大学院大学, 進化ゲノミクスユニット, 准教授 (40817558)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: cockroach / blattabacterium / genome evolution

Outline of Annual Research Achievements

In this project, I proposed to study the genome evolution of the cockroach endosymbiont Blattabacterium. Altogether, I sequenced >50 Blattabacterium genomes, all of which have been assembled and annotated. With these genomes, I attempted to identify the factors at the origin of genome reduction in endosymbionts. I found that mutation rate was the primary driver of genome reduction in Blattabacterium. I also found several examples of gene lost under relaxed selection. However, population bottlenecks, and the associated genetic drift, did not correlate with gene loss, suggesting that the Muller’s Ratchet, the dominant explanation for gene loss in endosymbionts, play no significant role in Blattabacterium genome erosion. This project already yielded one published paper, and one paper is under second review. A third paper will be submitted this year.