Abstract Detail

Mechanisms of rapid adaptation through the expression of “heterogenomicity”

Transposable elements shape the transcriptional landscape in woodland strawberry.

Transposable elements (TE) are an important major driving force in shaping the evolution of eukaryotic genomes. The majority of observed genome size variation across land plants is due to the proliferation of various TE families. Novel TE insertions may have deleterious effects on the host genome, and genomes have evolved various mechanisms, including RNA-directed DNA methylation, to suppress the activity of TEs. The epigenetic silencing of TEs by DNA methylation has also been shown to result in decreased expression of neighboring genes. Thus, the genome must balance the ‘trade-off’ of silencing TEs with negatively impacting the expression of its genes. Here, we examined the ‘trade-off’ hypothesis by examining a natural diversity panel of woodland strawberry (Fragaria vesca). We uncovered that genome sizes of diploid F. vesca from populations distributed across the northern hemisphere range between 184 to 408 million bases (Mb) with a median genome size of 229 Mb. This is among the greatest genome size variation (more than two-fold) documented in a single species that is not due to polyploidization. Furthermore, our analyses revealed that gene expression is not only negatively correlated with increased DNA methylation levels of nearby TEs, but that this has the potential to predict parental gene expression levels in intraspecific hybrids. Lastly, functional gene enrichment analyses suggest TEs may have played an important role in the adaptive radiation of this species and that unregulated TEs contributed to ‘genome bloat’ observed in some populations.

1 - Michigan State University, 612 Wilson Rd, East Lansing, MI, 48824, United States

Keywords:
subgenome dominance
hybrids
transposable elements.

Presentation Type: Colloquium Presentations
Session: COL06, Mechanisms of rapid adaptation through the expression of “heterogenomicity”
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 4:00 PM
Number: COL06004
Abstract ID:527
Candidate for Awards:None