ecosystem importance: single gene theory (Introduction)

by David Turell , Friday, April 01, 2022, 20:06 (965 days ago) @ David Turell

One keystone gene can destroy a vital species:

https://newsakmi.com/news/science/a-single-gene-in-one-species-can-cause-other-species-...

"But what if ecosystems not only hinge on a single species but can be made or broken by a single gene? In a study published on Thursday in Science, researchers have demonstrated the existence of what theycall a “keystone gene.” The discovery may have implications for how scientists think about the ways ecosystems, and the species in them, persist over time.

"In the lab, the researchers built several miniature ecosystems that consisted of just four species each. At the bottom of the food chain was Arabidopsis thaliana, a small annual plant that is a favorite study organism among biologists (its genome was sequenced more than 20 years ago). In each ecosystem, the plant served as food for two species of aphids, which in turn fed a parasitoid wasp.

***

"As the team expected, the ecosystems with more genetically diverse plants turned out to be more stable. For each plant with a different genetic makeup that the researchers added to the mix, the insects’ extinction rate fell by nearly 20 percent, compared with monocultures.

"But what stunned the researchers was that this result seemed to hinge on a single gene. Regardless of diversity, if systems contained plants with a certain variant, or allele, of the AOP2 gene, the extinction rate of the insects decreased by 29 percent, compared with systems without it. Essentially, if you change that AOP2 allele, you lose the insects. Increasing genetic diversity helped the insects because it increased the likelihood of the aphids encountering plants with this one critical gene variant. “We expected the diversity effect,” says lead author and University of Zurich ecologist Matt Barbour. “But the unexpectedly large effect of the single gene—that was surprising.”

***

"Conservation biologists have long known that diverse ecosystems are greater than the sum of their parts and that, in particular, they are more stable. Likewise, more genetically diverse populations of species are more likely to survive, thanks to an increased ability for them to adapt to a changing environment. The effect is akin to diversifying an investment portfolio: one cannot be sure which genes are going to lead to greater success as a population, so the more options one has, the more likely it is that something will come through.

"But the new findings point to a mechanism that could make genetic diversity critical for sustaining ecosystems. If specific gene variants—keystone genes—are lost from populations, other species could go extinct, not just the genes’ owners. “It isn’t really about genetic diversity but that, in having a diverse genetic pool, you’re increasing the chances of finding that singular important mutation,” Germain says. “That’s one of the things that’s cool about this paper—it might be something that not many ecologists have thought that much about.”

"Barbour says he does not suspect that keystone genes hold everyecosystem together. “I don’t expect them to be common,” he says. “But when they’re there, they’re going to be important.'”

Comment: the reason I presented this article is dhw's attitude about the need for food energy when he does not see to recognize how vital each system is for life to exist. These scientists did the study because of their concern that we might lose important systems. They are a vital part of the the living system that has been evolved over time that must support life. There is plenty of evidence about how humans unthinkingly damage systems