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A new study proves that a type of genetic element called 'introners' is the mechanism by which many introns spread within and between species.
It also provides evidence of eight instances in which introners have transferred between unrelated species in a process called 'horizontal gene transfer,' the first proven examples of this phenomenon. DNA is the genetic code that provides the biological instructions for every living species, but not every bit of DNA helps the species survive. Some pieces of DNA are more like parasites, along for the ride and their own survival. To translate DNA into proteins, the building blocks of life, many of these selfish DNA elements have to be removed from the genetic code. Doing so enables the body to produce the wide diversity of proteins that allow for complex life, but the process can also lead to health problems, like some kinds of cancer. University of California, Santa Cruz researchers are studying the ways that these genetic elements hide and make copies of themselves, so they can propagate within a species' DNA, or even hop from one species to an unrelated one in a process called "horizontal gene transfer." A new study in the journal Proceedings of the National Academy of Sciences proves that a type of genetic element called "introners" are the cause of many of these selfish genes spreading within and between species. It provides evidence for eight instances in which introners have transferred between unrelated species, the first proven examples of this phenomenon. "[Introners are] a way that genome architectures and complexity arise, but not necessarily because there is natural selection that favours this complexity," said Russ Corbett-Detig, senior author on the study and professor of biomolecular engineering at the Baskin School of Engineering. "A few may ultimately benefit the host, but most are just cheaters that found a really good way to hide in the genome," Russ added. In this study, the researchers have proven that introners are one of the main ways that new introns appear within a species' DNA. Introners are a kind of transposable element, a "jumping gene" that can move from one part of a genome to another, that have found a way to successfully make copies of introns throughout a genome. The team's past work has suggested this, but their advanced methods of searching the DNA of a wide range of species have now allowed them to definitively confirm their hypothesis. The researchers searched for introners in the DNA of thousands of species, something only recently made possible due to ongoing coordinated efforts to sequence a wide range of biodiversity and make the data publicly available, like the Earth BioGenome Project and the Sanger Tree of Life. (ANI)
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