Trilobites: The Evolutionary Event That Gave You Pumpkins and Squash
It’s been nice hanging out with you over the summer. But the seasons are changing, and it’s time I move on to pumpkins and squash. It’s not you, it’s me. You’re light, and sweet, and perfect for the summer. But as it starts to cool off, I just need the warm spices that go so well with that buttery hunk of pumpkin meat. Don’t be sad. I’ll see you again next summer.
Many of us have gone through these seasonal relationships with plants of the cucurbitaceae family. And although bittersweet, the opportunity to appreciate their diversity wouldn’t have been possible if it weren’t for an ancient event in plant evolution.
About 100 million years ago, the genome of a single melon-like fruit copied itself. Over time, this one ancestor became a whole family of plants with different colors, shapes, sizes, defenses and flavors, such as pumpkins, squash, watermelons and cucumbers, according to a paper published Thursday in the journal, Molecular Biology and Evolution.
The researchers compared the genomes and evolutionary trees of a number of plants including cucumbers, melons and gourds. Millions of years of environmental changes allowed the fruits to lose genes over time and tailor their own codes to become what we know them as today.
After each major divergent event, genes were deleted, chromosomes were rearranged and new genetic patterns were created. Xiyin Wang, an agricultural plant scientist at North China University of Science and Technology and lead author of the paper was surprised that no one had discovered this monumental evolutionary event. But he thinks that the complexity of the plants’ genomes may have made it difficult to properly analyze the genetic data until recent developments in genome sequencing.
Knowing more about which genes survived to do different things in each plant means scientists can now get closer to creating even more variations of these fruits. And there are other reasons to appreciate these differences — and how long it took this family of fruits to acquire them: when you’re over your pumpkin ravioli, pumpkin beer and pumpkin spice whatever — there’ll be a nice winter melon soup waiting for you.
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