Researchers have discovered that a small fern has the largest genome ever recorded, over 50 times the size of the human genome, surpassing the previous record holder, a Japanese flower. Some plants have immense genomes, a notable exception to the general trend of smaller genomes. The researchers wanted to study these giant genomes to understand better how they evolve and function in different organisms.
Through a detailed survey of six fork fern species in New Caledonia, the researchers identified T. oblanceolata as having the largest genome of any organism yet measured, at 160 billion nucleobases. Maintaining such a large genome is energetically costly, raising questions about its biological limit. Plant genomes can significantly vary in size, with different methods causing genome bloating, such as inheriting extra copies of chromosomes or accumulating long repetitive DNA sequences.
The research offers insight into how plants with giant genomes, like the fork fern, might have a history of repeated genetic bottlenecks, leading to the accumulation of deleterious mutations and junk DNA that contribute to larger genomes. Comparisons between the fork fern’s gene copies and those in aquatic ferns with smaller genomes could provide further clues into the evolution of extreme genome sizes. The study underscores the importance of using genome data to catalog biodiversity, focusing on less recognizable species like the fork fern, which may not be visually striking but holds significant biological marvels.
Understanding the evolution and function of giant plant genomes can shed light on fundamental biological processes and genomic architectures in various organisms. Cataloging genome data of diverse plant species and studying their genetic makeup can contribute to a deeper understanding of evolutionary processes and biodiversity conservation efforts. The findings also emphasize the significance of investigating less conspicuous plant species to uncover hidden biological treasures that are not immediately apparent to the casual observer.
