An international research team has unveiled a fascinating genetic phenomenon in lycophytes, ancient land plants akin to ferns. Published in the journal PNAS, the study reveals an extraordinary level of genetic stability in these plants, challenging conventional norms in plant genetics.
Lycophytes, specifically homosporous varieties, display a remarkably slow pace of genomic evolution, maintaining a consistent genetic structure for over 350 million years. The researchers sequenced the genomes of two homosporous lycophyte species, Huperzia asiatica and Diphasiastrum complanatum, which diverged from a common ancestor around 350 million years ago.
Surprisingly, approximately 30% of their genes have retained the same arrangement since their divergence, showcasing an unusual evolutionary pattern called synteny. This genetic stability is akin to discovering a “living fossil” at the genetic level, according to Dr. Li Wang, co-author of the study.
Notably, the researchers observed a significant retention of duplicated gene copies following whole-genome duplication events, a phenomenon typically rare. Contrary to expectations, these homosporous lycophytes preserved both sets of genes with minimal alterations, even after hundreds of millions of years of evolution.
Dr. David Wickell, a co-first author of the study, highlights the unusual retention of duplicate genes, noting that this observation challenges traditional ideas about how genomes reorganize after large-scale duplication.
While the precise reasons for this genetic stability remain unclear, the researchers believe that further exploration of homosporous plants could offer novel insights into plant genetics and evolution across all land plants. The study underscores the importance of preserving biodiversity, as these plants provide essential clues to Earth’s evolutionary history.