![]() ![]() For that reason, all eukaryotic cells are equipped with special genetic shears called spliceosomes. The Puzzle of Eukaryotic Genomesīecause of the introns polka-dotting their DNA, if the genes of eukaryotes were translated directly into proteins, the resulting molecules would typically be nonfunctional garbage. ![]() Their findings “might explain the vast majority of intron gain,” said Russ Corbett-Detig, senior author of the new paper and an evolutionary genomics researcher at the University of California, Santa Cruz. ![]() Moreover, they showed that introners could explain why explosive gains in introns seem to have been particularly common in aquatic forms of life. Last November, researchers presented evidence that introners have been doing this in diverse eukaryotes throughout evolution. These pieces of DNA can slip into genomes and multiply there, leaving profusions of introns behind them. How this tremendous, enigmatic variation in intron frequency evolved has stirred debate among scientists for decades.Īnswers may finally be emerging, however, from recent studies of genetic elements called introners that some scientists regard as a kind of genomic parasite. The genes of yeast, for instance, have very few introns, but those of land plants have many. The mystery of why eukaryotes rely on this baroque system deepened with the discovery that the different branches of the eukaryotic family tree varied widely in the abundance of their introns. When eukaryotes express their genes, their cells have to splice out RNA from the introns and stitch together RNA from the exons to reconstruct the recipes for their proteins. Instead, genes are split into segments, with intervening sequences, or “introns,” spacing out the exons that encode bits of the protein. In their DNA, the information about how to make proteins isn’t laid out in long coherent strings of bases. All animals, plants, fungi and protists - which collectively make up the domain of life called eukaryotes - have genomes with a peculiar feature that has puzzled researchers for almost half a century: Their genes are fragmented. ![]()
0 Comments
Leave a Reply. |