When we think of evolution, the gradual evolutionary change comes to mind: dinosaurs turning into birds, ancient forests transforming into the world around us. But therefore, all these upheavals hide a more subtle story, one that occurs at the level of plant DNA. It’s a story of conservation, persistence, and molecular information embedded in ancestral genomes that has survived hundreds of millions of years.
For decades, biologists puzzled over a strange contradiction. Genes themselves often remain strikingly similar across species, even when those species split apart eons ago. Yet the DNA that controls when those genes switch on or off, the so‑called regulatory DNA, seemed far less predictable. Rapid DNA turnover, genome duplications, and rearrangements seemed to erase the trail. Many wondered if plants had conserved regulatory sequences at all.
Now, a breakthrough has rewritten that narrative. In a sweeping study published in Science, researchers from Cold Spring Harbor Laboratory (CSHL) and collaborators worldwide uncovered more than 2.3 million conserved non‑coding sequences (CNSs), including over 3,000 predating angiosperms, from 284 plant species spanning 300 million years of diversification.
These ancient sequences weren’t just relics. They clustered near developmental regulator genes, like the HOMEOBOX family, and when researchers mutated them, plants showed dramatic changes in growth and form. In other words, these hidden switches are essential for life.
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Using a new computational tool called Conservatory, the team traced these sequences across 284 species. Some of these sequences are incredibly old, dating back more than 400 million years, long before flowering plants appeared.
The key to the study lies in careful analysis. They didn’t scan genomes broadly; instead, they examined gene clusters at a fine scale and compared their arrangement, on a tiny scale, from one ancestor to the next, across hundreds of species. It revealed conserved elements that older methods had missed.
CSHL postdoc Anat Hendelman, a co‑first author, admitted the team was stunned: “Picking apart and genetically editing these CNSs confirmed they’re essential for developmental function.”
The study also uncovered three guiding principles of CNS evolution in plants. First, Order matters: Even if spacing shifts, the sequence order along chromosomes stays consistent. Second, new links form: When genomes rearrange, CNSs can attach to different genes. And third, old guides endure: Ancient CNSs often persist after gene duplication, fueling the evolution of new traits.
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Zachary Lippman of CSHL explained, “We didn’t just find CNSs. We found that new regulatory sequences often come from old ones, reshaped after duplication. That’s how novelty emerges.”
This Conservatory project enables scientists to access a comprehensive atlas of plant regulatory DNA spanning crops and their wild ancestors. For plant biologists and breeders, this is more than an academic treasure; it’s a practical tool. Understanding how regulatory DNA has been preserved and reshaped could help fine‑tune crops to withstand drought, improve yields, and tackle food shortages.
But the implications stretch further. As Lippman put it, “It’s a new window into the evolution of life across eons and a new opportunity to engineer or fine‑tune crop traits more efficiently.”
Most of us have heard of deep space, the vast, star‑studded expanse beyond Earth. But scientists also explore something equally mysterious: deep time.
Deep time isn’t just an idea, it’s a living record etched into the DNA of plants. Decoding these ancient regulatory sequences allows scientists to solve a puzzle that has lingered for decades. Also, it opens new paths for agriculture and reveals fresh chapters in the story of life itself.
Journal Reference:
Kirk Amundson, Anat Hendelman, Danielle Ciren et al. A deep-time landscape of plant cis-regulatory sequence evolution. Science. DOI: 10.1126/science.adt8983