Science & Research

Gene swapping can cause adaptation

By
Contributing Writer
Wednesday, March 14, 2012

A study published last week in the journal Current Biology illustrates plants’ ability to swap genes with one another, not just pass them on from parent to offspring. Brown evolutionary biologists, along with researchers at other universities, demonstrated that Alloteropsis grasses held the ability to adapt through the swapping of genes – a radical shortcut in the evolutionary process.

The researchers, led by Pascal-Antoine Christin and Erika Edwards, postdoctoral researcher and assistant professor, respectively, in the Department of Ecology and Evolutionary Biology, found that specific species of plants from hot, tropical climates gradually adopted genes by laterally swapping with other plants. These genes eventually became integral aspects of the plants’ photosynthetic machinery. 

“The evolution of a new adaptation, whatever it is, requires the modification of pre-existing genetic material,” Christin said. These modifications often involve changes to enzymes, and these changes usually occur by natural selection between generations.

“What is so exciting here is that these genes are moving from plant to plant in a way we have not seen before,” Edwards said.

Though the idea of transferring genes within a generation could have important implications for the study of evolution, Christin said more work needs to be done before conclusions can be made about the larger impact, since the group only studied the Alloteropsis group – a set of plants which are exceptionally variable in terms of photosynthetic processes.

“We don’t know yet whether such a phenomenon occurs in different groups of plants,” Christin said. 

The researchers compared the genes for enzymes of C4 Photosynthesis, a specific type of photosynthesis that has advantages in certain environments. The researchers used phylogenetic analyses, a proverbial reconstruction of family trees, to see if some of the genes also belonged to the Alloteropsis group. Through their analysis, the researchers determined that these two sets of genes were incredibly similar to the distant lineages that evolved C4 photosynthesis independently.

In a response published with last week’s study, Washington State University professor Eric Roalson wrote that though horizontal gene transfer has been documented in some species, Edwards and Christin’s study is “the first well-documented case of plant-plant HGT of functional genes in which there has been a presumed adaptive advantage conveyed.”

The idea that plants may be able to use horizontal gene transfers to adapt to new environments could have important implications for the field, Roalson wrote, but future studies are needed to understand the underlying mechanism of the process.

Christin said while this phenomenon may not occur in all species of plants, the implications are far reaching. 

“The direct implication of this study is obviously to reveal a new evolutionary path to adaptation,” Christin said. “These results could have applied implications on a longer term.”

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