Functions and characteristics of genetic information obtained by horizontal gene transfer in insect genome

Research Project

Project/Area Number	17K07516
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Evolutionary biology
Research Institution	The Open University of Japan
Principal Investigator	Nikoh Naruo 放送大学, 教養学部, 教授 (70364916)
Project Period (FY)	2017-04-01 – 2020-03-31
Project Status	Completed (Fiscal Year 2019)
Budget Amount *help	¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000) Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000) Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Keywords	遺伝子水平転移 / 共生 / ゲノム
Outline of Final Research Achievements	We tried to detect genetic information acquired from bacteria through horizontal transfer in the poorly annotated genome of insects. At present, we focus on aphids and their close relatives. In aphids, seven genomes were examined, and several candidate genes are investigated for potential acquisition by horizontal transfer. In addition, we found the orthologs of the four known horizontal transferred genes of the pea aphid in the genomes of other aphids, and the palalogs in the related insects genomes. Using these sequences, we estimated the molecular phylogenetic position of the transferred genes in bacterial genes. The molecular phylogenetic analyses suggested that these four genes were acquired by horizontal transfer at the common ancestor of the aphids.From these results, we examined the characteristics and evolution of the horizontal transferred genes.
Academic Significance and Societal Importance of the Research Achievements	アブラムシに見られる細菌に由来する遺伝子は、アブラムシの共通祖先で獲得され、それが受け継がれてきたものであること、そしてこれらの４種類の遺伝子の機能が類似していることから、遺伝情報の細菌からアブラムシへの転移が、アブラムシとブフネラの共生に影響を与えたことが示唆される。一方で、ブフネラの祖先や現在のブフネラに由来する遺伝子がゲノム中に見られないことは、そのような水平転移がないか、少なくとも煩雑に生じないことを示している。これらのことは、生物の進化において、昆虫細菌間の遺伝子水平転移の新たな知見を示唆するものであり、学術的にも意義がある。