Susan Wessler

  • Sep 9, 2019

Date & Location: September 9, 2019, at 4p; Room 1200 Molecular Plant Sciences Building

Subject: Dissecting a transposable element burst: what is required, how has it evolved, and how does it spread?

Host: Ning Jiang

About the Speaker

University: University of California, Riverside

Abstract: Transposable elements (TEs) achieve high copy numbers through waves of amplification called bursts. For a TE to successfully burst it must be able to significantly increase its copy number without killing its host or being silenced by genome surveillance mechanisms. However, because the vast majority of TE bursts have been inferred after the fact – via computational analysis of whole genome sequence – the stealth features they require for success have remained largely undiscovered. Some features have recently been discovered by analyzing active bursts of the miniature inverted repeat transposable element (MITE) mPing and its autonomous partner Ping in four strains of domesticated rice (Oryza sativa, temperate japonica). First, mPing targets genic regions but avoids exon sequences, thus minimizing harm to the host. Second, because mPing does not share coding sequences with Ping, increases in its copy number and host recognition of its sequences do not silence Ping genes, thus allowing the continuous production of the proteins necessary to sustain the burst for decades. Additional insights into the mPing burst comes from analyses of an extensive collection of rice genomes including 3000 domesticated strains and a recombinant inbred population. While the survey of 3000 strains revealed that the burst is very recent and is restricted to a few closely related accessions, analysis of the sequences of 272 recombinant inbred lines demonstrated the potential of mPing to rapidly spread unimpeded through a large population.