Natural Epigenetic Variation in Sadhu Retroposons in Arabidopsis

The Arabidopsis genome contains a family of retroposons that are called Sadhu elements. One of these elements, Sadhu1-1, was previously shown to exhibit epigenetic variation with respect to DNA methylation among different wild-type accessions of Arabidopsis. Further, this variation was not strictly controlled by genetic variation acting in trans or by nucleotide polymorphisms at the locus, suggesting that this epigenetic variation was an example of an epiallele. It was also demonstrated that an inverse correlation exists between DNA methylation and expression of the Sadhu1-1 element. My project extended these findings by investigating the relationship between DNA methylation and nucleotide sequence variation at a second Sadhu element, Sadhu6-1. We found multiple strains that shared identical sequence at Sadhu6-1 but had varying methylation patterns. This finding demonstrates a situation where an epiallele exists at a retroposon that is not strictly determined by the underlying nucleotide sequence. We also found a negative correlation between DNA methylation and expression at Sadhu6-1, as was previously reported for Sadhu1-1. These findings suggest that DNA methylation is a regulating mechanism at Sadhu retroposons.

My Experience

I’m not entirely sure what I want to do after my senior year of college but even before my summer internship at BTI, I was already pretty sure that I wanted to be involved in scientific research. This experience was reassuring. Being given the opportunity to work on my own project with the guidance of a mentor, working at BTI gave me research experience that will be very valuable in preparing me for the future. Overall I had a wonderful experience working at the Boyce Thompson Institute. It is a great place to do research, my fellow interns were a joy to work with, and Ithaca is an awesome place to be.