Abstract Detail

Frontiers in fern gametophyte research

Der, Joshua [1].

Fern gametophytes in the genomics age.

The cost of high-throughput DNA sequencing technologies has dropped dramatically over the past few years. It is now possible to obtain genome-scale sequence information for any organism at moderate cost. This presents new opportunities for research investigating the evolutionary and molecular genetic basis of unique biological traits in diverse taxa. One of the most distinctive characteristics of ferns is the independent and mophologically distinct gametophyte and sporophyte generations of the fern life cycle. Often diminutive and cryptic, gametophytes have long been understudied, but are equally diverse in morphology, physiology, and ecology as their conspicuous sporophytic counterparts. Transitional between the gametophyte-dominated life cycle of bryophytes and the sporophyte-dominated life cycle of seed plants, ferns represent an important lineage for understanding the evolution of alternation of generations in land plants. Comparative transcriptome sequencing of gametophytes and sporophytes will be a key step in untangling this evolutionary mystery. While gametophytes and sporophtyes share the same genome, they undergo dramatically different developmental programs. What genetic (or epigenetic) features control these differences? Which genes are specifically or differentially expressed between gametophytes and sporophytes? Genomic technologies make investigating these questions possible. Furthermore, the ability to induce apogamy and apospory in some ferns allows us to separate the effect of ploidy on gene expression levels and the developmental fate of an organism. Additionally, natural selection is expected to act differently between the gametophyte and sporophyte generations, opening the possibility for genomic conflict between the two phases of the life cycle. This is due not only to the different ecological and physiological constraints placed on gametophytes and sporophytes, but because the strength of selection is greater in the haploid phase. What are the evolutionary consequences of this in ferns? Can we detect the signature of selection on "gametophyte genes"? Large scale gene family and phylogenomic datasets will opens the door to such investigations. High throughput sequencing technologies also present an opportunity for gene discovery and functional genomics in ferns.I will survey a few examples of genomic scale sequencing projects in ferns to highlight fertile research topics in fern gametophyte biology and evolution. Finally, I will present an argument for the need to sequence a fern genome.

Broader Impacts:

1 - Penn State University, Department of Biology, 201 Life Sciences Building, University Park, PA, 16802, USA, 814-777-7820

Keywords:
fern
gametophyte
life cycle
ploidy
transcriptome
RNA-Seq
Next-generation sequencing
Evolution.

Presentation Type: Symposium or Colloquium Presentation
Session: C4
Location: Prince of Wales/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 8:15 AM
Number: C4001
Abstract ID:932
Candidate for Awards:None