Introns have a bad rap these days. Sequestered with the rest of the (epi)genome in the term ‘junk’ DNA’; A reductionist way of describing 95% of our beloved genome as useless. But as new evidence keeps pointing out, introns and ‘non-coding’ regions actually code for most of the genomes products and/or function. In recently published work, forward thinking researchers created a handy ‘noise’-deciphering algorithm for predicting functional introns, and shown that once you find the appropriate methods for tuning into the ‘noise’, a lot can be deciphered.
A group lead by Dr. Liran Carmel (The Hebrew University of Jerusalem) set out to examine what determines if an intron is functional or not.
“…We focused on introns whose function comes about from microRNAs and snoRNAs that are embedded within their sequence. We built a data set of orthologous genes across 28 eukaryotic species, reconstructed the evolutionary histories of their introns and compared functional introns with the rest of the introns.” Dr. Carmel expands that “In our work, we assumed that introns can be either functional or non-functional, and we looked for features that would allow discriminating the two. We thought that “physical” features of the intron like sequence and length would not carry such information. Instead, we focused on features that characterize the evolution of each intron.” This appears to be the first time that the evolutionary features of introns were defined and used as an algorithm where miRNAs helped to identify intron locations.
Here’s what they computed:
- “Both families of RNA…settled within introns early during metazoan evolution”
- “…Several easily computable intronic properties that can be used to detect functional introns.”
When it comes to application; “Intron positional conservation is a new evolutionary conservation criterion that can be used to predict which introns have cellular function. Dr. Carmel concludes; “the motivation came from the surmise that functional introns would have different evolutionary pattern. We were happy to find that this is indeed the case.”
Check out your inner intron over at Nucleic Acids Research, September 2013