Without genetic variation, invasive asexual species must find other ways to adapt


July 30 (UPI) – All-female, invasive weevils transmit epigenetic changes to their offspring, helping them adapt to new environments, according to a new study.

In most of the animal kingdom, the ability of an organism to adapt and evolve depends largely on genetic variation.

Sufficient genetic diversity increases the likelihood that favorable traits will emerge and proliferate as the fittest specimens populate subsequent generations.

Some species, however, reproduce asexually, which means that their genetic reservoir is limited. So how do they adapt to new environments?

To find out, the researchers collected specimens of two asexually reproducing invasive weevil species, Naupactus cervinus and N. leucoloma, Florida, California and Argentina.

Although they share the exact same DNA, the researchers found that the weevil populations in each location produced different proteins to help them digest local plants.

Analysis of gene expression – detailed on Friday in the journal Plos ONE – showed that some plants elicited a more pronounced epigenetic response than others.

“We have found that certain groups of host plants, such as legumes, appear to be more taxing on weevils and elicit a complex gene expression response,” said study co-author Andrea Sequeira, professor of science. biologics at Wellesley College, in a press release.

“However, the weevil’s response to taxing host plants shares many differentially expressed genes with other stressful situations, such as organic growing conditions and the transition to new hosts, suggesting that there is a regime of ‘Shared gene expression conducive to evolution to respond to different types of stressful situations,’ Sequeira said.

The researchers also found that weevil mothers, who practice clonal reproduction, are able to “prime” their offspring with these epigenetic changes.

“Originally, we thought these changes would only be visible in a single generation,” said study lead author Ava Mackay-Smith, 2020 graduate of Wellesley College.

“When we studied larvae, which don’t yet have a mouth or eat plants, we found evidence for the same proteins and adaptations from their mothers,” Mackay-Smith said.

The results undermine previous assumptions that epigenetic instructions are lost between generations.

The researchers hope that by studying the mechanisms of epigenetic inheritance, researchers can develop better strategies to protect ecosystems from invasive asexual species.

“Knowing what’s in this insect’s repertoire, you might imagine that since we’ve now identified the proteins that are regulated differently, you could target a specific protein and design a targeted pesticide that only kills that weevil species,” without harming other native insects or wildlife, ”Sequeira said.


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