Explorations into the C-Fern Genome

In a little more than a decade, our understanding of plant genomes has increased immensely. Sequenced genomes are now available for every major green plant clade, from chlorophytic and streptophytic algae to a vast array of flowering plants - that is, every clade except the monilophytes (ferns).  Ferns are the most biodiverse clade of land plants after the angiosperms and sister group to the economically significant seed plants. Notorious for large genomes (~12 Gb) and numerous chromosomes (~3x more than the average angiosperm), fern genomes are largely unexplored despite their evolutionarily significant position as a reference group for analyzing ancestral versus derived genomic and genetic characters in the seed plants. Using transcriptomic, genomic, and chromosome fluorescent in situ hybridization techniques, we are delving into the genome of Ceratopteris richardii, a fast-growing tropical aquatic homosporous fern with a haploid genome size of 11.26 Gb and chromosome number of n = 39. We will present our results regarding gene specificity in the gametophytic and sporophytic life stages, gene density, and the role of polyploidy, retrotransposons, and small-scale duplications in the evolutionary genomics of this species. The outcome of this research will provide novel perspectives on the genomic dynamics and characteristics of this major clade, while also providing crucial resources for broader comparative genomic, phylogenetic, and developmental studies between ferns and seed plants, yielding new insights into the evolution of euphyllophytes as a whole.