It’s a phenomenon known to geneticists as “horizontal gene transfer,” a process by which one living thing takes in genes from another—as opposed to vertical transfer, which is child inherits genes from its parents.
For this, the two species must live close to each other, which would be conceivable in an aquatic environment not too far from a shore. But how to prove that such a thing really happened 500 million years ago? Chinese researchers, including the study was published on March 1, analyzed the genomes of 31 species representing various species of plants: among others, mosses, ferns, and charophytes, which are freshwater plants. They identified 593 families of genes considered to be “acquired” from bacteria, viruses or fungi. Many play a role in biological processes essential to life on land.
If this list does not constitute proof, its length is nevertheless impressive, comments the British biologist Jordi Paps in the New Scientist. Because while horizontal gene transfer between two species of bacteria has been documented for a long time, its role in more complex species remains “controversial,” he says.
At the same time, the same week this study was published, another one was also published reporting an ancient horizontal gene transfer, this time between bacteria and a microscopic aquatic creature of the rotifer class, called bdelloïde. The transfer would have occurred 60 million years ago and would have brought him an enzyme which would be one of the elements contributing today to its adaptation to the different freshwater environments of the planet.
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